Central Coast AVAs

Established on 23 October 1985, the Central Coast AVA spans from Santa Barbara County in the south to the San Francisco Bay Area in the north. The boundaries of the Central Coast include portions of ten counties (Alameda, Contra Costa, Monterey, San Benito, San Francisco, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz).  The Central Coast AVA is about 250 miles long, it’s only an average of 25 miles wide.

There is a range of mountains that run parallel to the Pacific Ocean along the California coast, and the valleys that extend west to the ocean from these mountains make perfect growing regions for cool climate loving grapes like Pinot Noir and Chardonnay. In fact, Chardonnay is the most widely planted grape in the region.

Generally more moderate temperatures, even in the warmer sections, that will lead to higher acidity, slightly lower alcohol. Although there are unique and sought-after variations in the Sub-AVAs, the Central Coast is mostly known for its Chardonnay, Pinot and Rhone varietals. Bordeaux varietals will lean toward less alcohol, lighter body and a bit more acidity, although the areas around Paso Robles and Santa Ynez can produce some lush full-bodied wines.

With around 100,000 acres planted to wine grapes, Chardonnay accounts for more than half of the total. Within this larger AVA are several smaller appellations that share the same cooling influence from the Pacific Ocean.

The cooler AVAs include Santa Cruz Mountains AVA which in addition to Cabernet Sauvignons also produces delicious Pinot Noir. Santa Lucia Highlands AVA in Monterey Country is a Pinot Noir go-to AVA.  Arroyo Seco AVA near the Santa Lucia Mountains has great Riesling and Rhone varietals. Edna Valley AVA near San Luis Obispo is known for its Chardonnay and Pinot. Further south, Sta. Rita Hills AVA is producing world-class Pinot Noir, Chardonnay and Syrah.

With this much area there are differences in the climatic influences that shape wine aroma and flavor characteristics. The northern portion extends from San Francisco to Monterey, with the area around Santa Cruz one of the most notable. This region is one of the few coastal regions that is known for their Cabernets.

The midsection of the AVA starts around Monterrey and heads south to San Luis Obispo. Influenced by the Monterey Bay and the wind-swept coastline, this section is notably cooler. Chardonnay dominates here, and toward the south end of this section some Merlot.

The bottom of the Central Coast Ava starts around San Luis Obispo and reaches down into Santa Barbara County. The warmest of the AVA’s sections, you’ll find a fair amount of Cabernet Sauvignon and Merlot, particularly around Paso Robles. As you head further south to Santa Barbara, more Rhone varietals and Pinot Noir are found.

Some of the warmer AVAs include Paso Robles AVA which is producing lush Rhone varietals and dusty, smoky Cabernet Sauvignon. Santa Maria Valley AVA, a great source for Rhone varietals, and Santa Ynez AVA which also produces amazing Rhone varietals and the heat loving Bordeaux varietals.

Adelaida District AVA

Established on 8 October 2014, Adelaida District AVA is located on the north west portion of the Paso Robles AVA in San Luis Obispo County.  The Adelaida District AVA is the most northwestern of the 11 wine regions of Paso Robles.  Its mountainous topography is ideal for viticulture, allowing vineyards to be established on sites with favorable aspects.

Adelaida District AVA's most inland border extends along the west bank of the Salinas River, and runs between the city of Paso Robles and the town of San Miguel, where it meets the northern San Miguel District AVA. The AVA lies in the Santa Lucia Range with high mountain slopes grading to foothills and ranging from 900 to 2,200 feet in elevation.  The Adelaida District AVA covers 53,342 acres with 883 acres planted as vineyards. 

There is a modest maritime influence from the Pacific Ocean as the warm air of the Paso Robles area rises, mixing with the cool moist air on the coast, creating fog that will roll in and out of Estero Bay to the west. A vacuum effect is created that brings cooling winds into the Paso Robles AVA.

Further south of the Adelaida District AVA, the Templeton Gap AVA sees these winds standing up flags, but back up in the north, these winds are less dynamic but with equal cooling power. The diurnal variance of the Adelaida District AVA can vary between morning lows of 50 degrees Fahrenheit to afternoon highs of 95 degrees Fahrenheit in the height of summer.

A mere 25 miles from the coast, Adelaida District AVA's proximity increases the influence of the Pacific Ocean. It receives light cooling breezes rolling in off the sea with some accompanying marine fog. Rainfall too is on the higher end when compared to neighboring AVAs, with an average of 25 inches annually.  On exceptionally wet years, vineyards have measured up to 45 inches of precipitation, and somewhere around nine inches in dry years.

The Adelaida District AVA's calcareous soils (characterized by a high volume of calcium carbonate from underlying chalk and limestone) consist of shallow, bedrock residual soils and patchy colluvial hillside soils.

Luckily, the calcareous soil has both water retentive capabilities and good drainage. This duality comes as a result of much of the calcareous rock being porous, like a sponge, and yet because it fractures easily, it allows water to travel deeper into the bedrock. The sponge-like qualities prove to be important as vines grow deep seeking out moisture during the warm summers. 

The most widely planted varieties in the Adelaida District AVA are Mourvèdre, Zinfandel, Cabernet Sauvignon, Syrah, Grenache and Merlot.

Alisos Canyon AVA

Established on 23 August 2020, Alisos Canyon AVA is located in Santa Barbara County due east outside the small town of Los Alamos on U.S 101 and about 20 miles south of Santa Maria. This is two hours north of Los Angeles and 45 minutes from downtown Santa Barbara.

The Alisos Canyon AVA lies entirely within the multi-county Central Coast AVA and does not share boundaries with another AVA. Alisos Canyon AVA stretches west to east over 9 square miles (5,774 acres) approximately 238 acres.

The AVA is located approximately 25 miles from the Pacific Ocean and is situated in a transitional region, between the cooler coastal regions and the warmer inland areas. Growing degree day accumulations within the Alisos Canyon are higher than those of the regions to the northwest and southwest, which are closer to the ocean, and lower than those in the more inland regions to the south and east.

The marine-influenced climate is also the basic viticultural feature of the Central Coast AVA. The climate of Alisos Canyon is affected by cool marine air which travels into the area via the drainage system of San Antonio Creek.

Soils within the Alisos Canyon AVA are primarily derived from weathered sandstone and shale. The most common soils are the Paso Robles Formation and Careaga Sandstone, which comprise 63 percent and 13 percent of the total soils, respectively. High calcium content from shale pebbles increases the thickness of the skins of red varietal wine grapes, which in turn increases the color and tannin levels in the resulting wine. High sand content provides excellent drainage for vineyards, thus reducing the risks from certain pests such as nematodes and phylloxera.

The low clay content of Careaga Sandstone soils reduces the uptake of nutrients and reduces the vigor of the vines, resulting in smaller grapes with a higher skin-to-juice ratio than grapes of the same varietal grown in different soils with higher clay content.

The AVA's location is a “Goldilocks Rhone Zone,” meaning that temperatures are neither too hot nor too cold for growing Rhone wine varietals such as Syrah, which is the most common varietal grown in the canyon.  The USDA plant hardiness zone for the AVA is 7b.

As a result of the distinct meso-climate and specific soil characteristics, Alisos Canyon produces amongst the finest Rhone style wines on the West Coast with elegant flavor, expressive aromatics and significant longevity. Syrah, Grenache, Grenache Blanc and Petite Sirah are among the standouts in Alisos Canyon.

Arroyo Grande Valley AVA

Established in 3 January 1990, the Arroyo Grande Valley AVA is located in San Luis Obispo County. It is part of the larger Central Coast AVA.  It is found just seven miles from the northern border of Santa Barbara County and the Santa Maria Valley AVA.

The Arroyo Grande Valley AVA is located in a valley that cuts inland from the town of Arroyo Grande, covering the land within the Arroyo Grande Creek valley and the canyons and valleys immediately to the south. The valley is oriented in a northwest direction with its northeastern end around the Lopez Lake reservoir, 16 miles inland. The land to the north of Arroyo Grande Valley AVA falls under the Edna Valley AVA.

The 16 miles long appellation benefits from its east-northeast orientation which allows the breeze from the Pacific Ocean to moderate the climate of the area.  The orientation of the valley causes air from the cold Pacific Ocean to be funneled up the valley, and much of the lower part of the AVA is shrouded with fog for a good part of the day with cold ocean winds.  These climatic conditions are well suited to cool-climate-loving varieties, letting them develop rich varietal character without losing acidity.

Further inland, the higher altitudes and shelter from the prevailing winds mean there is a distinct fog line, past which the fog ceases to have such an effect on the vineyards.

The altitudes lead to a diurnal temperature variation, where warm days are followed by cold nights, lengthening the growing season and resulting in grapes with a good balance of ripeness and acidity.

The soils in Arroyo Grande Valley vary, but the most distinctive are the calcareous deposits of limestone left by an ancient ocean bed. These are free-draining and often quite shallow. This part of the Californian coastline has been particularly ripped up by tectonic activity over time, and these limestone soils are joined by volcanic rock and alluvial loam soils.

The valley is divided by a fog line produced by the cool coastal fogs where Zinfandel, Petite Syrah and Rhône varietals are grown on the higher elevations near Lopez Lake and the cooler mid-valley vineyards being home to Chardonnay and Pinot Noir.

Arroyo Seco AVA

Established on 14 April 1983, the Arroyo Seco AVA is in Monterey County, southeast of Monterey Bay.  A large and diverse geographical area, Monterey County is located about an hour south of the famed Silicon Valley. Part of California’s Central Coast, the County is a special place endowed with a magical coastline. Monterey County's coastal influence from the rugged Pacific Ocean is just one of many unique aspects which contribute to rare and unparalleled grape-growing attributes.

Monterey County's primary winegrowing region is found within the Salinas River Valley. With dramatic mountain ranges to both the East and West, the Salinas Valley includes many prominent AVAs, including the Arroyo Seco AVA.  The Arroyo Seco AVA encompasses 18,240 acres in the valley adjacent to the Arroyo Seco Creek.

Positioned north-to-south, the Salinas River Valley begins at Monterey Bay and the Pacific Ocean. A direct and unobstructed corridor from the ocean, the valley is considered an Open Throat. The unique “open” geography creates a Thermal Rainbow, whereby as one moves south away from Monterey Bay the temperature rises dramatically. The Thermal Rainbow effect is heightened in Monterey County because of a very rare and relatively unknown, subterranean trench found just offshore at Monterey Bay. 

The 'Blue Grand Canyon' is a very deep marine canyon similar in size and scope to the Grand Canyon. Not necessarily apparent above water, the deep underwater canyon affects the level of regional cooling; the saturation and penetration of fog as well as the strength of winds that sweep through the Salinas Valley. The result of this rare geographic condition is extreme cooling and regional temperature variances, all of which contribute to the uniqueness of Monterey County as a grape growing region. 

Another rare condition found in Monterey County’s Salinas Valley is a north-south orientation. Unlike most other marine-influenced river valleys and wine growing regions, which are oriented east-west, the Salinas Valley is bifurcated from the Pacific Ocean to the west by the Santa Lucia Mountains. This natural geographical boundary creates a Rain Shadow that impacts the region and contributes to its semi-arid nature. The Rain Shadow contributes to the Salinas Valley generally receiving 13 inches of rain per year, but sometimes achieving less than 10 inches of rain per year. The arid conditions result in increased stress on the vines, diminished yields, as well as stimulating root growth into different subsoil zones. 

In general the winegrowing region benefits from an arid climate as well as direct exposure to the Pacific Ocean. Of course what makes Monterey County different from other appellations, and thereby special, is the rarity of the dramatic geographical conditions.  The area has a cool climate, and is best suited for those grape varieties that benefit from the cool afternoon breeze.

The Arroyo Seco AVA is known for its gravelly soil, specifically of the Arroyo Seco Gravelly Sandy Loam type, and of Chualar Loam.

First planted in 1961, the Arroyo Seco AVA now consisting of approximately 7,000 acres planted to vines for premium vineyards, the Arroyo Seco AVA was one of the first California viticulture regions to be planted to Chardonnay.  Today, the Arroyo Seco AVA is one of the largest planted regions for Chardonnay grapes in the United States and has also bult a reputation for award winning Sauvignon Blanc.  Another rising star of the Arroyo Seco AVA is the Musqué clone of Sauvignon Blanc.

Ballard Canyon AVA

Established on 1 October 2013, the Ballard Canyon AVA is located in Santa Barbara County. The 7,800 acres designated area lies west of Ballard and Solvang townships while in the center of the Santa Ynez Valley viticultural area, which in turn, is within the perimeter of the larger multi-county Central Coast AVA.

Ballard Canyon itself is a long, thin canyon that runs in a curve from north to south and is surrounded by a myriad of smaller canyons interspersed with dry, rugged hills. The distinguishing features of the Ballard Canyon AVA include wind, temperature, and soils.  The USDA plant hardiness zone for the AVA is 9b.

Winds are funneled into the Santa Ynez Valley from the Pacific Ocean via a gap between the Santa Rita Hills and the Purisima Hills. However, the north-south orientation of Ballard Canyon shelters the vineyards from the worst effects of these maritime influences. Fog flows in from the coast in the early hours of the morning and retreat again in the afternoon. The vines in the south of Ballard Canyon AVA are exposed to the fog for a longer period of time compared to those planted at the higher elevations in Ballard Canyon AVA's northern vineyards.  These factors, in combination with high diurnal temperature variations of approximately 40 Fahrenheit degrees, slows the ripening process enough that acidity levels are not compromised. The wines produced are therefore balanced and fresh.

The soils in the Ballard Canyon AVA are more uniform than in the larger Santa Ynez Valley viticultural area. They are made up of sand and clay loam with good drainage capacities. Limestone is also present in certain northern vineyard plots. Vines planted in the steeper vineyard sites are able to develop deep root systems in search of water in the area's arid environment, thereby increasing vine strength. A good level of calcium in Ballard Canyon AVA's soils ensures the development of thick skins and increases the concentration of tannins, sugars and acids in the grapes. This helps to produce richly flavored, well-balanced wines.

The Ballard Canyon AVA area which has long been highly regarded for its red wines made from Syrah and Grenache. The viticultural area contains about 7,800 acres where planted vineyards account for approximately 565 acres. Syrah constitutes the primary varietal planted within Ballard Canyon AVA.  In addition, there are a preponderance of other Rhone varietals, both red as well as white varietals.  Red varietals account for about 80% by acreage and white varietals account for the other 20%.

Carmel Valley AVA

The Carmel Valley AVA is in Monterey County, east of Carmel-by-the-Sea.  Carmel Valley AVA is within the larger Monterey County AVA and 100 miles south of San Francisco. It is located in a narrow valley that runs south from Monterey Bay into the Santa Lucia mountains.

The Carmel Valley AVA is home to a number of wineries and vineyards, as well as the town of Carmel Valley Village.  County Route G16 runs through the valley while the Carmel River flows on the valley floor.  The vineyards in the region are mostly located at 1,000 feet above sea level or higher, where coastal fog and wind less influence the crops.

Vineyards in the Carmel Valley AVA are subject to a warmer microclimate than other regions in Monterey.  Site selection that takes altitude and aspect into account provides grape growers with a way to protect their vineyards from the prevailing winds and can ensure that the fog which sometimes covers the lower valley does not reach high enough to affect the vines there.

Vines in Carmel Valley AVA can reach altitudes of up to 2200ft. This means that while daytime temperatures are heightened by more intense sunlight, night-time temperatures can be significantly lower. This diurnal temperature variation is one of the biggest in Monterey, and the lengthened ripening period it causes brings flavor complexity to the grapes.

The Carmel Valley AVA soils, made of sandy and gravelly loam, are nutrient-poor and free-draining, causing the vines to struggle and grow deep root systems to access water in the ground. These deep-rooted vines tend to be healthier and stronger and can produce grapes with a greater concentration of flavor.

There are two distinct viticultural areas within the Carmel Valley AVA. Most vineyards sit on the slopes of Cachagua Valley in the southern reaches of the zone. The mountainous terroir here is well suited to the Bordeaux varieties of Cabernet Sauvignon and Merlot, which make up the majority of plantings in the AVA.  The Carmel Valley AVA is responsible for some of the best Cabernet Sauvignon wines made in Monterey County.

Vines can also be found in the lower-lying areas surrounding the town of Carmel Valley in the north of the AVA. Here, cooling winds and fog that are funneled up the valley from the Pacific Ocean cause lower overall temperatures and make the area well suited to the production of cool-climate varieties such as Pinot Noir and Chardonnay.

Chalone AVA

Established on 13 June 1982, the Chalone AVA is in Monterey and San Benito counties, located in the Gabilan Mountains east of Soledad.  Chalone AVA is an isolated AVA clinging to the side of the Gabilan Mountain range.  Located about halfway up the eastern side of the Salinas Valley.  The 8,640 acres region is named for the nearby Chalone peaks.

The effects of terroir in Chalone AVA are amplified by the dry, windy climate. While the area is exposed to intense sunshine, high altitudes and cold breezes from the nearby Monterey Bay keep it cool enough to produce elegant wines.

The Gavilan Mountain range provides an undulating landscape with vineyards found nestled amongst its foothills. Vignerons are able to use this to an advantage and plant plots with an aspect to encourage ripening and flavor accumulation in the grapes. 

A huge fluctuation in temperature between day and night effectively slows ripening, letting the berries develop rich aromatics and flavors while retaining good acidity. The wind also helps to keep the bunches free from rot and additionally stresses the grapes, contributing to their smaller size.

The star of Chalone AVA's terroir is undoubtedly the soils.  The region has limestone and decomposed granite soil.  The shifting San Andreas Fault that runs through this part of California has deposited decomposed granite soils in the area, and this is complemented by pockets of limestone, which come from decayed marine organisms from an ancient sea floor.

The soil profile in Chalone AVA is often compared favorably to that of Burgundy. It is shallow, dry and free-draining – perfect for the cultivation of premium fruit.

Vines have to struggle for survival, producing small, thickly skinned berries that can have an excellent concentration of flavor. Much has been made of the translation of these soils into the wine itself; it is often said that flinty, stony characters in the wines come directly from the influence of the ground in which they are grown.

Vines were first planted in Chalone AVA in the early 1900s by a French immigrant who was inspired by the potential of the region for the production of the Burgundy varieties.  The area is home to the production of particularly Chardonnay and Pinot Noir.

Cienega Valley AVA

Established on 18 August 1982, the Cienega Valley AVA is located just south of the town of Hollister in western San Benito County. It is part of the larger Central Coast AVA.

The thin valley covered by the Cienega Valley AVA juts northwest into the Gabilan Range under the watchful presence of Mount Harlan (home to the Mount Harlan AVA) to the southwest. The San Benito AVA runs the length of the Cienega Valley's eastern boundaries, from north to southeast, with the Paicines AVA region a little way further east.  The Monterey AVA is on the other side of the Galiban mountains.

Vineyards in the Cienega Valley AVA sit on the valley floor and along the higher ridgelines, sometimes reaching altitudes of up to 1,100ft.  The valley floor is divided by the San Andreas fault.

The climate in Cienega Valley AVA is moderate, because the area is protected by surrounding mountain ranges from both the cool Salinas Valley in the west and the hot Central Valley in the east. Warmth during the day is moderated by cooling breezes from Monterey Bay, and a diurnal temperature shift sees temperatures drop in the evenings.

The famous fault line that Cienega Valley AVA sits on contributes significantly to the geology of central California. It effectively splits the soil profile of the valley into two distinct areas.

On the western side, the soils are made up of granite and limestone, while on the eastern side they are granite and sandstone. Although geologically different, these soil types are both excellent for the production of quality grapes – both are free-draining and restrict vigor and grape yields, leading to more-concentrated flavors in the berries.

Viticulture in Cienega Valley AVA is largely accredited to a French settler named Theophile Vache, who first planted grapes here in the early 1850s. Now, Cienega Valley AVA hosts a handful of producers making interesting wines from a range of grape varieties.

The AVA is said to contain some of the oldest Pinot Noir grapes in California.  The terroir is also well suited to the production of complex, elegant red wines made from Zinfandel, Cabernet Sauvignon and old-vine Negrette.

Creston District AVA

Established on 8 October 2014, the Creston District AVA is located in the south east portion of the Paso Robles AVA in San Luis Obispo County.  It is located in the vicinity of the small community of Creston.  The Creston District AVA covers a plateau at the base of the La Panza Range and is bisected by the Huerhuero Creek as it runs towards the Salinas River.

Creston District AVA has elevations ranging from 1000-2000 feet as its boundaries encompass the foothills of the La Panza Range which extends southeast, covered by the Los Padres National Forest.

Creston District AVA is not the most southeasterly of the Paso Robles area AVAs, however, as the Paso Robles Highlands District AVA lies beyond it to the east. Creston District AVA is also bordered by the El Pomar District AVA and the Paso Robles Geneseo District AVA at its northwestern point, roughly in the middle of the Paso Robles AVA.

The Creston District AVA covers 46,794 acres with 1,365 planted in vineyards. It lies on an old erosional plateau at the base of the La Panza Range with alluvial terraces and fans of Huerhuero Creek.

Despite its easterly location, Creston District AVA benefits from moderate sea breezes passing through the Templeton Gap, a small break in the coastal range of hills midway along Paso Robles' western boundary, roughly around the York Mountain AVA. The breezes sometimes carry marine fog and bring a cooling effect to the vineyards, which are largely planted on west- and southwest-facing slopes to maximize these effects.

Cool air can also drain off the La Panza Range, where it travels down Huerhuero Creek and over the plateau in the evenings. Creston District AVA has a relatively low annual average rainfall of 11.5 inches, because it falls in the shadows of both the La Panza Range and the Santa Lucia Range, though this is mitigated in part due to abundant groundwater along the Huerhuero Creek.

The Creston District AVA's soils consist of old, well developed terrace and hillside soils and are a mix of granite and sedimentary rock which were brought in through water ways over time. A combination of loam and high granitic content allows for deep rootstocks and good drainage.

The most widely planted grape varietals in the Creston District AVA are Cabernet Sauvignon, Syrah, Zinfandel, Merlot, Petite Syrah.  Grenache and Mourvèdre can also be found here.  The Grenache, Syrah and Mourvèdre are used for the region's southern Rhône blends.

Edna Valley AVA

Established on 11 May 1982, the Edna Valley AVA is located in the south-western corner of  San Luis Obispo County, encompassing the rural town of Edna, which is south of the county seat San Luis Obispo and north of the small coastal town Arroyo Grande. The Edna Valley AVA lies in the larger Central Coast AVA. The valley is roughly bounded by Lake Lopez to the south and Islay Hill to the north. The valley runs east to west, bounded to the west by the Santa Lucia Mountains.

Thanks to the cooling moist winds which travel up the Edna Valley from the Pacific Ocean and morning fog, the climate here is much cooler than that experienced further inland. Just across the Los Machos hills is Kern County, where temperatures are significantly higher (and rainfall significantly lower), and just beyond that is the California High Desert.

With moderate sunshine, cool maritime fog, and rich oceanic and volcanic soils, the Edna Valley AVA has California's longest growing season. This extended growing season gives complex flavors to the grapes. Grapes hang longer on the vine here, resulting in higher levels of phenolic ripeness and increased varietal character in the finished wines.

The region also has a complex array of soils, most of which are well-suited to quality viticulture. Much of the valley was once part of the Pacific Ocean and ancient marine sediments have left a fertile base. The soil is further enriched with dark humus, loam and clay.

The first vines were planted here in the early 1800s, and winemaking remains popular today. The area's naturally varied landscape offers various options for vineyard site selection – one of the reasons why winegrowing has continued here successfully for so long.

The terroir in the Edna Valley AVA is well suited to Chardonnay and Pinot Noir, both of which are renowned for their ability to produce fine wines in cooler climates. These two Burgundian varieties dominate plantings in Edna Valley AVA vineyards, although Syrah, one of California's up-and-coming varieties, is hot on their heels and producing some very well-received wines. Rich, aromatic Viognier – Syrah's white counterpart from the Rhone Valley – is also doing well.

El Pomar District AVA

Established on 8 October 2014, the El Pomar District AVA is to be found in Paso Robles Wine Country which is located in San Luis Obispo County.  El Pomar District AVA is immediately southeast of the city of Paso Robles, roughly in the centre of the overall Paso Robles wine region.  Its southern border increases in elevation and is characterized by the foothills of the La Panza Range, with the elevation of the whole AVA ranging from 740 to 1600 feet.

The western border of the El Pomar District AVA is adjacent to the Templeton Gap District, with the Rinconada fault demarcating the two. To the north is the Geneseo District while off to the southeast is the Creston District.

El Pomar falls in the shadow of the Santa Lucia Range, which influences its modest rainfall average of 15 inches annually. The region lies squarely within the path of air circulating through the Templeton Gap and, as a result, it is significantly affected by the Pacific Ocean.

Sea breezes cool El Pomar and can bring marine fog as well. Cold air also drains off the La Panza range along the southern border bringing additional cooling affects. However, because of the hilly topography of the region, the risk of frost is low.

The soil is composed of underlying granite and sandstone with good drainage, and the topography is shaped by terraced alluvial fans left by old waterways.

The predominant grapes of El Pomar do not vary much from those of the wider Paso Robles, or the wine styles of the greater Central Coast. Cabernet Sauvignon and Merlot are dominant, with some Syrah grown for use in southern Rhône-style blends along with Grenache and Mourvèdre.

Gabilan Mountains AVA

Established on 14 August 2022, the Gabilan Mountains AVA is located in Monterey County. 

The 98,000-acre area covers the 30-mile long mountain range of the same name in Monterey and San Benito Counties.  This represents (physically) the northeastern boundary of Monterey County and the southern end of San Benito County, and is part of the Central Coast AVA.  It also contains the Chalone AVA and the Mt Harlan AVA.

From south of San Juan Bautista to east of Soledad, the roughly 30-mile-long appellation is primarily defined by its high elevation: 2,370 feet on average, and no lower than about 1,500, keeping the vines above the soupy fog that soaks most of Monterey.

There’s plenty of open grazing land in the region that would be suitable for future vineyards, but the dry climate is a limiting factor. It’s very difficult to get water up to these elevations.  The dramatic diurnal temperature swings from hot, arid days to very cool nights only amplify those qualities.

Soils are mostly decomposed granite, with some rare outcrops of California limestone and chunky white streaks of calcareous shale.  The granite soils are thin so that the vines have to dig deep into the earth to reach the water.  This really stresses the grapes which produces intense, bold flavors that really stand out from the valley floor grapes.

The wines from the area are said to show a certain “crushed rock” minerality alongside intense fruit, with plenty of backbone.  The grape varietals grown in the area are Pinot Noir, Chardonnay, Syrah, Grenache, Bordelaise, Aligoté and Viognier.

Hames Valley AVA

Established on 24 March 1994, the Hames Valley AVA is located in Monterey County about 2 km west of US Route 101.  It is part of the larger Monterey AVA, and is located at the southern end of the Salinas Valley, in the foothills of the Santa Lucia Range, that runs southward from Monterey Bay toward San Luis Obispo County.  Hames Valley AVA lies just west of the town of Bradley and about 20 miles north of the Paso Robles AVA.

Hames Valley is too far away from Monterey Bay to feel the influence of the winds that are funneled down the Salinas Valley from the Pacific Ocean. Consequently, Hames Valley has one of the hottest and driest climates of Monterey.

The diurnal temperature variation is an important feature of the terroir. During the growing season, hot days are followed by significantly cooler nights, sometimes dropping up to 50°F (38°C) in temperature. This cooling-off period slows ripening in the grapes, giving them time to develop rich aromatics without sacrificing essential acidity.

The free-draining soils are made of loam with pockets of rockier shale. Fracture lines in the soil allow root systems to penetrate deep into the ground for water and nutrients.  These soils, when combined with the low rainfall in Hames Valley, encourage low yields and small berries with a high skin-to-juice ratio. The resultant wines are rich and concentrated with firm tannins and intense, bold flavors.

Hames Valley AVA currently has 2,000 acres planted to vineyards.  Big, full-flavored wines made from Syrah and Petite Syrah are a speciality of the area. Other varieties produced in Hames Valley include Cabernet Sauvignon, Merlot and Zinfandel, and some port-style fortified wines made from Tinta Cao, Touriga Nacional and Tempranillo. 

Happy Canyon of Santa Barbera AVA

Established on 7 October 2009, the Happy Canyon of Santa Barbara AVA is located in Santa Barbara County.  The smallest AVA in Santa Barbara County, when measured by land under vine, it covers 37 square miles (23,941 acres) with 492 acres of planted vine. The area comprises canyon terrain, hills, and river and creek basins to the east and south of the San Rafael Mountains, northwest of Lake Cachuma and north of the Santa Ynez River.

Elevations within the Happy Canyon of Santa Barbara AVA range from 500 feet in the southwest corner to 3,430 feet in the northeast corner, in the foothills of the San Rafael Range is situated in the east of the Santa Ynez Valley.

The Happy Canyon of Santa Barbara AVA climate is warm – the warmest microclimate within the wider Santa Ynez Valley – but the vineyards are cooled by the ocean fog, which rolls inland off the Pacific Ocean in the morning, and burns off again in the afternoon sun when temperatures can reach around 90°F in the summer months.  Temperatures can even top 100 degrees on summer days, and drop dramatically at night, down 50 or 60 degrees, even in July and August. That diurnal shift is ideal for the Bordeaux varietals.

The Happy Canyon of Santa Barbara AVA's vineyards consist of nutrient-poor and mineral-rich soils, varying from sandy and clay loams to cherts and serpentine cobbles. The soils are rocky mixtures that are rich with minerals and tend to yield concentrated wines.

Vineyard plantings began here in the late 1990s, with the area producing its first vintage in 2001.  The grapes which thrive in the Happy Canyon of Santa Barbara AVA fit firmly into the template of the classic Bordeaux vineyard: Cabernet Franc, Cabernet Sauvignon, Merlot, Petit Verdot, Malbec and Sauvignon Blanc. Typical Rhône Valley grape varieties are also represented here, led most notably by Syrah.

Lamorinda AVA

Established on 23 February 2016, the Lamorinda AVA is in the San Francisco Bay Area located due east of the Berkeley Hills in Contra Costa County encompassing the region around the cities of Lafayette, Moraga and Orinda. The name Lamorinda is a portmanteau from the names of the three locales defining the region: Lafayette, Moraga, and Orinda.

The Lamorinda AVA is a region within the existing San Francisco Bay AVA and the larger, multicounty Central Coast AVA stretching approximately 30,000 acres (47 sq mi).  The terrain is composed of moderate-to-steep hills with narrow valleys. The steep hillsides prevent the use of machinery for vineyard work instead requiring the work to be done manually. The terrain contrasts with the steeper, more rugged terrain to the south and west and the lower, flatter plains to the north and east.

Additionally, Lamorinda AVA is characterized by a distinct suburban land use pattern which tends to provide property owners with enough room to plant vineyards large enough for commercial viticulture. This contrasts with the more urban and densely populated areas to the east and west.

The AVA is suitable for both cool and warm-climate varietals because the hilly terrain results in disparate levels of sunlight at different elevations. The Berkeley Hills affect the local climate by their elevation. The oceanic marine layer, which develops during the summer, bringing fog and low clouds with it, is usually less than 2,000 feet deep and thus is blocked by the range. This produces a "fog shadow" effect to the east, which is warmer than areas west of the hills. The westerly wind that carries the marine layer through the Golden Gate typically splits its flow as it hits the Berkeley Hills producing a southerly wind from Berkeley northward and a northerly wind in the direction of Oakland.

In winter during spells of tule fog inland, a reverse situation occurs, with the fog usually confined to areas east of the hills. Rainfall is also affected by the higher elevations when westerly winds from the Pacific is perpendicular to the hills during a storm and forced to rise, cooling and condensing additional moisture, increasing the precipitation on the western slopes but leaving areas east of the hills drier.

Lamorinda AVA's position in the hills protects it from the famous San Francisco Bay fog, and the vineyards have far less influence from the ocean than the surrounding areas. Instead, there is a range of different microclimates throughout the area that are more dependent on altitude, slope and aspect of the vineyards.

The dominant geological formation are the Orinda Formation, while the Briones and Mulholland Formations are also present. These underlying geological formations affect viticulture due to their role in forming the soils of the region. Other geographic formations dominate the surrounding areas. 

Soil is an important consideration for Lamorinda AVA. The hills are made of uplifted sedimentary rock, and are covered with clay-rich soils. However, these soils are thin and sandy, and this, combined with the steep slopes, makes for excellent drainage in the vineyards. The lack of water in the soil reduces the threat of mildew, and decreases vine vigor, which helps direct energy into the production of high-quality berries.

Lamorinda AVA covers approximately 139 acres. The USDA plant hardiness zone for the AVA is 9b.  Lamorinda AVA in is far from being a commercial winegrowing area, instead hosting a number of small home wineries making just enough wine to satisfy the local demand.

Cabernet Sauvignon is planted at the base of the hills, while the earlier-ripening Pinot Noir prefers the higher vineyards. Other popular varieties of the AVA include Chenin Blanc and Petite Syrah.

Lime Kiln Valley AVA

Established in 3 June 1982, the Lime Kiln Valley AVA is located in the larger Cienega Valley AVA in San Benito County.  The Lime Kiln Valley AVA occupies a long, narrow valley and its offshoots that cuts a rift roughly southwest into the Gabilan Mountains, the range that separates San Benito from Monterey in the west. The Mount Harlan AVA lies just to the west of Lime Kiln Valley AVA.

The valley takes its name from its once-thriving limestone mining and kilning industry of the 1890s, the remnants of which can still be seen scattered throughout the area today.  Lime Kiln Valley AVA is one of California's smaller AVAs, covering just 2300 acres, of which only a tiny percentage is under vine.

Lime Kiln Valley enjoys a climate in which warm, sunny days precede long, cool nights. While the valley is fairly sheltered, some cooling breezes from the cold Monterey Bay find their way into the vineyards through the Pajaro River Gap.  The area has a wide diurnal temperature variation of up to 50 °F, leading to a longer growing season, with daytime temperatures in 85 °F to 95 °F range during the summer growing seasons. 

This results in the grapes retaining acidity, which is especially important when balancing the big, high-alcohol red-wine styles produced here.

The soil in the region is composed of foundations of limestone and dolomite with sandy, gravelly loam above.  Vines thrive in the Lime Kiln Valley AVA's decomposed granite and limestone soils (formed by the action of the San Andreas fault and floodwaters of the last Ice Age), with plentiful groundwater encouraging them to grow deep root systems. Both bush vine and trellising systems are employed in the vineyards here.

The Lime Kiln Valley AVA is home to planted varietals such as Mourvedre, Gros Verdot, Zinfandel and Syrah.

Livermore Valley AVA

Established on 31 August 1982, the Livermore Valley AVA is in Alameda County, surrounding the city of Livermore in the Tri-Valley region.  The AVA lies directly east of San Francisco city with the majority of its western boundary covered by the wider San Francisco Bay AVA (of which it is a part) and also within the even larger Central Coast AVA. 

Livermore Valley AVA vineyards surround the town of Livermore in a valley that runs eastwards from the Pleasanton Ridge Regional Park, just east of San Francisco Bay.  Its northwestern tip, just west of Danville, abuts the Lamorinda AVA while the wider, sprawling Central Valley AVA lies a little way to the east.

There is a wide variation of terroir in the Livermore Valley AVA, ranging from gentle hills to ancient river beds.  Livermore Valley AVA lies on a unique east-west orientation, unlike many other winegrowing valleys.  The climate is Mediterranean in nature, with hot, dry summers followed by mild, rainy winters.  The valley is surrounded by low hills which serve as a climatic buffer from the famous fog of San Francisco. Instead, cool ocean breezes provide the temperature-moderating effect in Livermore Valley.

Warmer influences from the inland Central Valley are cooled by these breezes in the late afternoon, and there is often a significant diurnal temperature variation. This ensures that grapes are given a chance to cool overnight, slowing the ripening process and ensuring flavor complexity in the grapes.

The deep, gravelly soils in Livermore Valley are excellent for the production of premium grapes. Their drainage capabilities mean that vines grow deep root systems to access the water and nutrients in the ground.

The groundwater basin underlying the valley is the Livermore Basin, the largest sub-unit of which is the Mocho Subbasin. The Livermore Basin is one of five aquifers in the San Francisco Bay Area that supply most of the metropolitan Bay Area population. The entire Livermore Basin aquifer faces a concern over elevated total dissolved solids by the year 2020 due to an expanding human population leading to higher rates of return water flows to the aquifer containing certain salts.

Livermore Valley AVA is considered a Winkler Region III grape growing zone with temperatures comparable to northern Napa Valley appellations such as St. Helena or Calistoga.

Livermore Valley AVA, is an area which has been known for premium wines made from Sauvignon Blanc and Semillon, although changing tastes and viticultural experimentation have led to Chardonnay and Cabernet Sauvignon vines being grown in the area too.

The Petite Syrah grape produced Livermore's best historically known red wine, although the climate also makes for interesting dessert wines as well as excellent Cabernet Sauvignon, Merlot, Sangiovese, and Rhone varieties.

There is also a move afoot among the wineries in Livermore to specialize in Cabernet Franc, Chardonnay, Sauvignon Blanc, Merlot, Cabernet Sauvignon, and some other mostly Bordeaux varieties.

Los Olivos District AVA

Established on 20 January 2016, the Los Olivos District AVA is located in Santa Barbara County.  Los Olivos District AVA is approximately 30 miles inland from the Pacific Ocean, it straddles the Santa Ynez Valley, formed by the Santa Ynez River, between the Purisima Hills above Solvang.  The area encompasses the townships of Los Olivos, Ballard, Santa Ynez and Solvang. State Route 154, known locally as the San Marcos Pass Road or Chumash Highway, bisects the region accessing many of the wineries and vineyards as it traverses toward its destination in Santa Barbara.

The Los Olivos District AVA stretches over 22,820 acres where there are vineyards cultivated on 1,120 acres.  The AVA shares its western boundary with the eastern border of the Ballard Canyon AVA and its eastern boundary flanks the western perimeter of Happy Canyon of Santa Barbara AVA while not overlapping with either AVA.  It is located within the Santa Ynez Valley AVA and the larger, multi-county Central Coast AVA. 

The distinguishing features of the Los Olivos District AVA include its topography, soil, and climate. The AVA is located on a broad alluvial terrace plain of the Santa Ynez River. The topography is relatively uniform, with nearly flat terrain that gently slopes southward toward the Santa Ynez River. The lack of steeply sloped hills reduces the risk of erosion and facilitates mechanical tilling and harvesting in the vineyards. The open terrain allows its vineyards to receive uniform amounts of sunlight, rainfall, and temperature-moderating fog because there are no significant hills or mountains to block the rainfall and fog or shade the vineyards.

In this region, the temperatures are affected by cooling marine fog. However, Los Olivos District AVA is located about 30 miles inland from the Pacific Ocean, so much of the marine fog has diminished by the time it reaches the area in the late afternoon.  The thin fog allows the daytime temperatures to rise higher and the nighttime temperatures to drop lower than in the regions farther to the west, where heavy fog is present throughout the day.  The region to the east receives even less fog than Los Olivos District AVA, so daytime temperatures rise higher and nighttime temperatures drop lower. The warm daytime temperatures within the AVA encourage fruit maturation and sugar production, and the cool nighttime temperatures minimize acid loss.

Over 95 percent of the soils within the Los Olivos District AVA are from the Positas-Ballard-Santa Ynez soil association and are derived from alluvium, including Orcutt sand and terrace deposits. The soils are moderate to well-drained gravelly fine sandy loams and clay loams with low to moderate fertility. The soils drain quickly enough to reduce the risk of root disease but do not drain so excessively as to require frequent irrigation. Soil nutrient levels are adequate to produce healthy vines and fruit without promoting excessive growth. By contrast, the majority of soils in the surrounding regions are not from the Positas-Ballard-Santa Ynez soil association and are generally less fertile and drain faster.

The USDA plant hardiness zone for the Los Olivos District AVA is 9b.  More than just geographically positioned between the AVAs of Happy Canyon of Santa Barbara AVA and Ballard Canyon AVA, Los Olivos District AVA is also a rough middle ground in terms of climate and wine styles.  The length of its growing season is an average of the two regions, with its popular grape varieties including Sauvignon Blanc, Cabernet Franc, Cabernet Sauvignon, Merlot and Sémillon as well as cool-climate varieties like Syrah, and also includes Spanish and Italian varietals. 

Monterey AVA

Established on 14 June 1984, the Monterey AVA is located in eastern Monterey County.  It is part of the larger Central Coast AVA. It runs roughly 100 miles from its northern point, north of Monterey Bay to its southern point, abutting Paso Robles.  The Monterey AVA is a long, thin viticultural area and it traces the Salinas river valley from the San Luis Obispo county line in the southeast to the river's mouth 90 miles away in the northwest.

Although within the Monterey County, the Monterey AVA is a separate area, covering a total of 640,000 acres.  The Monterey AVA includes parts of the Carmel Valley and the Salinas Valley, and contains five smaller American Viticultural Areas.

The Salinas is the largest river of the central coast of California and is vital to the success of viticulture in the area.  It stretches for 170 miles, draining a land area of 4160 square miles. On its route between the Los Padres National Forest and the Pacific, it passes through Paso Robles and San Lucas before it even reaches the Monterey County line. Once north of the border the river runs through the heart of the Hames Valley AVA, San Bernabe AVA and Arroyo Seco AVA, and the Monterey AVA.

The Monterey AVA valley floor is in classic Californian style, flat and several miles wide creating ideal topography for grapevines. It runs between the Gabilan Mountains and the Sierra de Salinas acting as a natural funnel, drawing cool air inland from the coast.

The northern portion is a cool growing region, but one with a very long growing season. Daytime temperatures rarely exceed 75 °F in most parts of the region, although the southern part of the Monterey AVA reaches 100 degrees at times. 

Fog and cool breezes are a vital part of the Monterey AVA terroir, just as they are further north in Napa and Sonoma valleys. As the largest of all of the county's AVAs, the region is home to considerable variations in microclimates and soil types.  Dominate soil types are loam based.  The soil is sandy and most regions require extensive irrigation from the Salinas River.

Approximately 40,000 acres of wine grapes are currently cultivated in the Monterey AVA.  Over 50% of the grapes grown in the Monterey AVA are Chardonnay. In the northern area, the area closer to the cold Pacific Ocean, Pinot Noir, Riesling and Chardonnay are the predominant varieties, while warmer pockets further south have more plantings of Cabernet Sauvignon, Merlot, Syrah and Zinfandel.

Mt. Harlan AVA

Established on 14 November 1990, the Mt. Harlan AVA is located in San Benito County. It is located high in the Gabilan Mountains, a range of coastal mountains which run north-west to south-east along the boundary of San Benito and Monterey counties, and is part of the larger Central Coast AVA.  The AVA boundaries encompass almost 7,500 acres.  The AVA almost immediately east of Mt Harlan AVA is Lime Kiln Valley AVA and the wider Cienega Valley AVA.

Nestled in California's Coast Ranges, 22 miles from the coast and at an altitude of roughly 2,000ft, Mt Harlan AVA is one of the highest, coolest and driest AVAs in California. While the landscape of scrubby, part-forested hillsides resembles that of northern Spain, the climate is closer to that of southern Burgundy, with little rain, cool winds, consistent sunshine and a long growing season.

Although the mountain after which the Mt Harlan AVA is named peaks at roughly 3,800ft above sea level, the vines are planted in a single band about halfway up the slope. This elevation was chosen to give the vines enough sunshine exposure to reach full ripeness without having to endure the strong, cold winds which characterize the microclimate further up.

As a result of the dry conditions, Mt Harlan AVA vines often experience a degree of water stress, causing them to dig deep, strong root systems. Another effect of the environment is that the vines give low yields of small berries, resulting in wines with concentrated flavors and aromas.

At elevations of 1,800 feet to 2,200 feet above sea level, the soil is predominantly limestone. Only about 100 acres are under vine. 

The benefits of limestone on Chardonnay and Pinot Noir grapes are famously demonstrated in Burgundy, so with a Burgundian climate and a Burgundian soil type, the two varieties were the obvious choice for Mount Harlan's terroir. Jensen has also experimented with Aligoté, Burgundy's other white grape, to critical acclaim.

Pacheco Pass AVA

Established on 11 March 1984, the Pacheco Pass AVA is located in the Santa Clara and San Benito counties of California, near Pacheco Pass.  It is part of the larger San Francisco Bay AVA. The pass is a 15 miles long corridor between the San Francisco Bay area to the west and the San Joaquin Valley to the east. State Route 152 passes through the center of the wine region.

The Pacheco mountain pass is an important (and supposedly haunted) 15-mile route through the Diablo Range connecting the San Francisco Bay area to the Central Valley. The vineyards can be found at the southernmost end of the Santa Clara Valley, just a few miles from the equally obscure San Ysidro District AVA.

The topography in the Pacheco Pass AVA is characterized by gently rolling hills. Wind is sucked into the area through the Pajaro River Gap, which opens up to the cold waters of Monterey Bay in the west.  Pacheco Pass AVA also feels warming influences from the hot Central Valley that lies across the Diablo Hills in the east. It is this moderate, transitional climate that makes Pacheco Pass AVA suitable for grape growing – vines that experience warm sunshine and cooling winds have a longer growing season, leading to a greater balance of ripeness and acidity in the grapes.

Because of its elevated location near the San Francisco Bay, the Pacheco Pass AVA is very windy. There is a large wind farm at the top of the pass that supplies power to the local electrical grid.

During summer, day time highs are usually between 80 and 95 degrees Fahrenheit. A few days may rise above 100 degrees, but this is quite rare. Rainfall is very low in the AVA and is usually less than 10 inches a year. During the growing season, it is very unusual for it to rain. Most of this precipitation occurs between November and April.

The region is on the border of more extreme temperatures. To the east, the San Joaquin Valley has much hotter summers and colder winters. Because of the moderate climate of Pacheco Pass, spring frost rarely hurts the grapes.

The region has a number of natural artesian wells in the local soil.  At its highest elevation, the road reaches an elevation of about 1,300 feet. Pacheco Peak rises to 2,845 feet above sea level.

The San Luis Reservoir is in the eastern part of the region. This man-made body of water is used to irrigate local agriculture. A significant amount of the water is also diverted to the Central Valley Water Project and the California State Water Project. The Los Banos Creek Reservoir, San Felipe Lake, and Pacheco Creek are also both in the AVA. The path of Pacheco Creek has left significant gravel and sand deposits.

Pacheco Pass AVA's few vineyards grows several different grapes in this climate, Cabernet Sauvignon, Merlot, Chardonnay and Gewurztraminer.

Paicines AVA

Established on 15 August 1982, the Paicines AVA is located in San Benito County, named after the town of Paicines.  The Paicines AVA is the southernmost AVA in San Benito County, and is part of the larger San Benito AVA.  The Paicines AVA covers an area inside a valley about 12 miles south of the city of Hollister.  It is separated from Monterey by the Galiban Mountain range, which is home to the Chalone AVA further south.

The Paicines AVA has the warmest climate in San Benito County, mostly because it is the least elevated, but cooler than the wine regions of the Central Valley.  However, cooling ocean breezes are funneled into the valley from the cold Monterey Bay, which serves to bring temperatures down overnight, extending the growing season. The vineyards are relatively exposed on the flat valley floor, exacerbating the cooling effects of the wind. This exposure means that fog does not often settle in Paicines AVA.

Sandy soils with gravel and limestone components are scattered throughout the region. The soils are of varying depths and often provide good drainage, which forces the vines to grow deep root systems to access the water in the ground, thus strengthening them. 

Most of the grapes grown in the Paicines AVA are supplied to wineries outside the region.   Previously associated with the production of bulk wine in the 1980s and 1990s, the region is now home to some premium vineyards producing higher quality wines made of Merlot, Cabernet Sauvignon and Chardonnay. 

Paso Robles AVA

Established on 3 October 1983, the Paso Robles AVA is located in San Luis Obispo County. At that time there were 556,765 total acres with a little over 5,000 under vine. In 1996, the AVA expanded by 52,600 acres and then again by 2,635 acres in 2008.  Finally, in 2014, 11 smaller AVAs were established within the Paso Robles AVA.  The sub-division recognizes the diverse growing regions in Paso Robles, with altitudes ranging from 700 to 2400 feet, a range of soils, and varying degrees of regional influence of the marine effects of the Pacific Ocean.

Paso Robles AVA is a large winegrowing area towards the southern portion of California's Central Coast AVA region. At 666,500 acres the official Paso Robles AVA is among California's very largest; it effectively covers the northern half of San Luis Obispo County.

The Paso Robles AVA's northern limit is marked by the county line with Monterey County, from where it stretches southwards along the Salinas river valley for about 35 miles. It stops just short of San Luis Obispo city, just on the other side of which lies the Edna Valley AVA and Arroyo Grande Valley AVA. Its western edge is defined by the Santa Lucia coastal mountains, beyond which lies the Pacific coastline.

Despite its proximity to the Pacific Ocean, Paso Robles AVA's climate is remarkably warm and continental. This is due largely to the hills that lie between the main vineyard areas and the coast. These shield the area from climate-moderating coastal influences, meaning hot days and cool nights almost everywhere within the AVA.

The region is not entirely bereft of refreshing coastal breezes, however, thanks to the "Templeton Gap". This is not a single gap per se, but a series of narrow river valleys that bisect the Santa Lucia range, collectively allowing Paso Robles AVA to "breathe" cool, coastal air in the afternoon and early evening.  Regions vary in climate largely due to their proximity to the Templeton Gap and their relationship to the shielding effects of the Santa Lucia range and the Temblor Range to the east. 

The scale of soil diversity throughout Paso Robles AVA is tremendous and it is not unusual to have several types within one vineyard site. Primarily, bedrock is composed of weathered granite, volcanic and marine sedimentary rocks overlayed with shallow combinations of sandstone, mudstone or calcareous shales. This is a stark comparison to the deep, fertile soils predominately found elsewhere in California.

Grapes were first introduced into the Paso Robles area in 1787. Commercial wine growing, however, was not started until the 1880s.  The Paso Robles AVA now has close to 40,000 vineyard acres planted with wine grapes.

Today, wine from Paso Robles wines are typified by rich, ripe reds based on warm-climate varieties such as Zinfandel, Cabernet Sauvignon, Merlot and the Rhone Valley trio Grenache, Syrah and Mourvedre, along with Viognier and Roussanne. The majority are made from these warm-climate varieties but Pinot Noir and Chardonnay are also found, mostly in the very coolest vineyards of the region.

Paso Robles Estrella District AVA

Established on 8 October 2014, the Paso Robles Estrella District AVA is one of the larger of the 11 newer AVAs in the Paso Robles region, on California's Central Coast. Located to the northeast of Paso Robles city, the district lies in the central north of the Paso Robles AVA, between the Cholame Hills and the Salinas River as it runs north towards Monterey County.

The northern tip of the district runs along the boundary of San Luis Obispo and Monterey County, which is also the northern border of the greater Paso Robles region. Paso Robles Estrella District AVA's eastern border roughly follows a line of peaks in the Cholame Hills (part of the Temblor Range), beyond which the terrain becomes much steeper, with an arid climate and isn’t part of any of Paso Robles AVAs.

To the southeast, however, lies the San Juan Creek AVA and the Paso Robles Geneseo District AVA is tucked up against the Paso Robles Estrella District AVA's southern boundary (roughly along the line of State Route 46 as it runs east of Paso Robles). To the west, Paso Robles Estrella District AVA is bordered by the San Miguel District AVA and Adelaida District AVA.

At approximately 66,800 acres, this area is largely valley floor type topography and floodplain to the Estrella River.  It is bisected by the Estrella River as it feeds into the Salinas River, and falls in the shadow of the Santa Lucia Range to the west. The influence of the mountain range decreases the rainfall in lower elevations with average annual precipitation of 12.5 inches in the valley floor.  The highest average rainfall is 15.5 inches at peak elevations, with the Paso Robles Estrella District AVA lying between 745 and 1,819 feet above sea level and shaped into a series of terraces and foothills. Vineyards are planted on flat surfaces and various slope angles and aspects.

The Paso Robles Estrella District is cooled by air drawn through gaps in the Santa Lucia Range by a vacuum formed when the land surface temperature is warmer than the Pacific Ocean. Cool breezes also travel south up the Salinas River from Monterey Bay.  Evenings can bring cold air rolling down from the higher elevations towards the convergence point of the valleys, which can lead to fog the next morning.

Well-drained alluvial soils sit close to the surface with some pockets of land capable of better water retention beneath them.  The soils are generally made up of sandy loam along the creeks and valley floors, while higher terraces have more gravel and clay content.

The terroir is quite perfect for the cultivation of premium wine grapes, warm days that do lead to cool nights, moderate soil rooting depths control vigor in vines, and tempered water stress produce complex fruit flavors.

Red varieties that do well in the Estrella include Cabernet Sauvignon, Syrah, Merlot, Petite Sirah, and other Bordeaux varieties such as Mourvèdre and Grenache. White varieties seen to be doing well include Sauvignon Blanc, Viognier, and Chardonnay. 

Paso Robles Geneseo District AVA

Established on 8 October 2014, the Paso Robles Geneseo District AVA in the Paso Robles region, on California's Central Coast.  Positioned front and center in the original Paso Robles AVA is the Paso Robles Geneseo District AVA, located approximately 11 miles east of Paso Robles.

The Paso Robles Geneseo District AVA is sized at approximately 17,300 acres, this region is largely made up of a series of terraces surrounding the Estrella River and Huerhuero Creek.

Through uplift from the Huerhuero and La Panza Fault, elevations in the region range from 740 – 1,300 feet above sea level. Much like stairsteps, these terraces rise and fall across the region which gives growers options in aspect, being able to plant on southwest, southeast, northwest, and northeast exposures as necessary.

This relatively warm region benefits from the cooling influences of the Templeton Gap effect. This commonality for most of the regions in the Paso Robles AVA brings cool air from the Pacific Ocean over the Santa Lucia Mountain Range, fluctuating day to night temperatures by up to 50 degrees Fahrenheit. The result is that it provides a prime opportunity for grape clusters to ripen and yet cool off overnight. This influences positive sugar production during the day and allows the skins and acid to develop in the evening, ultimately leading to well-balanced wines between alcohol, tannin, and acid.

The soils in the Geneseo District are mostly made up of silty clay and clay loam, with some decomposed calcareous material well below the surface. These soils range from more acidic in the clay material (5.6 – 6.5 pH) to more alkaline in the calcareous zones (7.9 – 8.4 pH). This can influence vigor, depending on how densely impacted the soil is, but it is common for there to be moderate soil rooting depths with moderate water stress, and modest to low nutrient levels.

Stressed out vines can develop some very complex fruit flavors, so winemakers look to grow many of the Bordeaux varieties in this region, along with some Rhône, like Syrah, which happens to be some of the oldest planted in all of Paso Robles.

New plantings have slowed in the region, much to do with the limited water supply within the below ground aquifer, but the Paso Robles Geneseo District AVA continues to mature. Wines from the district are known for pronounced aromas and flavors, and its fruit is often sourced by brands from all over the Paso Robles AVA.

Paso Robles Highlands District AVA

Established on 8 October 2014, the Paso Robles Highlands District AVA lies at 60,300 acres, making it the second-largest in the Paso Robles AVA. This region fills in the south-east quadrant of the Paso Robles AVA with the San Juan Creek AVA outlining its northern edge. Although the area has been sparsely settled, with no formal town or settlement, historically it has been known as a vast cattle ranching area. The name, “Highlands” is a name that residents of this area have traditionally referred to it as since at least the late 1800s.

The Paso Robles Highlands District sets itself apart topographically from the central and western regions of the greater Paso Robles AVA. The terrain includes large expanses of wide-open landscape and grasslands, high ridges with scattered pine trees, something only seen in the western Paso Robles AVAs. There are also lower hills and terraces that are only split by canyons and arroyos from seasonal streams. These canyons and streams appear as long fingers that run predominantly south to north across the landscape.

The Paso Robles Highlands District AVA has the highest consistent elevation than all the other AVAs in Paso Robles with a range of 1,160-2,086 feet (most vineyards are at 1,200-1,600 feet). At 33 miles from the Pacific Ocean, this region generally has a warmer and more continental climate with less precipitation than other regions of the Paso Robles viticultural area at similar elevations. An interesting point is that due to its location to the east of the Santa Lucia Range and northeast of the La Panza Range, it lies in a double-rain shadow. However, due to its relatively higher elevations, the Highlands District still receives an average of 12 inches, which is a little more than some of the other Paso Robles AVAs to the north and west.

The diurnal temperature changes that exist throughout the Paso Robles AVA help exemplify what makes the region unique. The Highlands District is an example of what would be the greatest day to night temperature change as it has the greater daily, monthly, seasonal, and annual temperature ranges when compared to other areas within the Paso Robles viticultural area. The difference between daily maximum and minimum temperatures in the mid and late-summer can be 50 °Fahrenheit or more, with highs around 100 °Fahrenheit and lows around 50 °Fahrenheit.

According to grape growers in the region, the warm summer days ensure the full maturity of the fruit, while the cool evenings preserve acids in the grapes. The growers also note that due to its distinctive climate, grape harvest in the proposed viticultural area occurs two to four weeks earlier than in some other areas of the Paso Robles viticultural area.

The soil in the region is predominantly sandy loam along the creeks, loams on the small alluvial fans, and coarse sandy loams to clay loams on the hillsides. Many of the subsoils are cemented by calcium carbonate, which can cause vines to struggle for the first five to 10 years until they reach deeper down to find iron-based clay. This increases vigor in the vines and produces a lot of intensely rich fruit.

While more than 20 different varieties are grown here, both white and red.  The AVA is mostly planted to Petite Syrah, Zinfandel, Syrah, Cabernet Sauvignon, Chardonnay, Sauvignon Blanc, Chenin Blanc, and Valdigue.

Paso Robles Willow Creek District AVA

Established on 8 October 2014, the Paso Robles Willow Creek District AVA is one of the smaller AVAs in the greater Paso Robles viticultural region in San Luis Obispo County.  The Paso Robles Willow Creek District AVA gets its name from the creek and watershed known as Willow Creek which runs through the center of the district.  Paso Robles Willow Creek District AVA's northern border is characterized by the mountainous terrain of the Santa Lucia Range and a decline in elevation towards the Salinas River floodplains to the east. In the very northeast corner it meets the boundaries of Paso Robles City.

The Paso Robles Willow Creek District AVA is a relatively high elevation, truly mountainous area of the coastal range. The slopes become more steep, elevated, and dramatic in the northern portion of the AVA.  The Paso Robles Creek watershed, a direct tributary of the Salinas River, runs east-west and originates from the range crest. Feeding the Paso Robles Creek are the smaller tributaries Jack Creek, which runs north-south at the western edge of the Paso Robles Willow Creek District AVA, and Willow Creek, which sits more to the center of the district and also runs north-south.

The Paso Robles Willow Creek District AVA sits squarely on the Highway 46 corridor that ushers in the Templeton Gap effect and so is highly influenced by the Pacific Ocean.  Marine effects combined with its relatively high altitude of 960 to 1,900 feet leads to the region's high average precipitation of 24-30 inches annually.  The overall cooler climate in comparison to neighboring AVAs means that Paso Robles Willow Creek District AVA vineyards have a longer growing season and therefor harvest taking place two to three weeks later than the Paso Robles average. The soil type of Paso Robles Willow Creek District AVA are largely calcareous in nature with patches of alluvial clay-loams found adjacent to the creek.

Cool-weather, compared to the rest of the Paso Robles AVA, persists in the Willow Creek District. Fog from the coast infiltrates the mountain gaps and spills into different plateaus and arroyos which often are the same paths for consistent ocean breezes. The Templeton Gap effect also helps to cool more southern portions of the Willow Creek district where the boundary lines blur between the eponymous Templeton Gap District. These winds are far more pronounced than the aforementioned breezes, however, the combination of the two is what defines this region as a II on the Winkler and Amerine scales.

At the southeast border the district boundary is marked by a change in soil to the Monterey formation of hard alluvial bedrock. The soils of the district are made up of soft marine shale, mudstones and sandstone with alluvial sediment following various waterways.

All soils in the Paso Robles Willow Creek District AVA tend to be young to intermediate in age with pH values of 7.8 – 8.9 common.  Many of the soils have not only active lime weathered from soft calcareous shale fragments, but the evolution of secondary lime within the soil profiles and complexes. Other complexes of calcareous origin include the Calodo-Linne complex of alkaline clay loams, the Nacimiento-Ayar-Diablo complex of clay loams, and smaller areas of Ryer and Rincon clays and clay loams, and Croply and Gazos clays.

What is interesting is how soils combine to create interesting growing environments and when alone can be completely opposite of one another. The Calodo and Linne soils are different in terms of vineyard potential, as the Calodo soil is much shallower, and can be more challenging to dry farm, producing low vigor vineyards. The deeper Linne soils have greater rooting depths and water-holding capacities, producing low-moderate vine vigor. The soil series that extends eastward from the Paso Robles Willow Creek District AVA throughout the Templeton Gap District is the deeper Linne series, which is common on older alluvial terraces and benches.

Within the Paso Robles Willow Creek District AVA region the Syrah and Southern Rhône red varietals are strongly represented along with Cabernet Sauvignon and the white grape Viognier. 

San Antonio Valley AVA

Established on 7 June 2006, the San Antonio Valley AVA, is located along the Diablo Range in eastern Santa Clara County.  The locale is bordered by Alameda County to the north and Stanislaus County to the east.  While still within Monterey, the region is relatively isolated from the main zones of grape growing and wine production, much like the (similarly parallel) Carmel Valley to the northwest.  Only the small Hames Valley AVA in the south forms a bridge between San Antonio Valley AVA and the wider Salinas Valley zone. San Luis Obispo County, and Paso Robles AVA, lie to the southeast.

The valley is located about 10 miles southwest from, and parallel to, the upper Salinas Valley, where most of the wine production in Monterey takes place. San Antonio Valley AVA is a watershed for the San Antonio River, which flows into Lake San Antonio at the southern end of the valley. The Pacific coast is 15 miles further southwest.  The San Antonio Valley AVA lies at an elevation of 2,133 feet.

This bowl-shaped mountain valley enjoys a warm, dry climate.  San Antonio Valley AVA's sheltered position away from the cold winds that buffet the Salinas Valley means that it is considerably warmer and drier than much of Monterey. However, some cool ocean breezes make their way into the valley in the afternoons, and a cooling morning fog is sometimes produced by Lake San Antonio.

The relatively high altitude of the vineyards, between 500ft and 2000ft above sea level, means that intense sunlight during the day is followed by much colder nights and mornings. This diurnal temperature shift ensures that grapes are given a cooling-off period each day, extending the growing season and allowing for the development of rich fruit characters in the grapes without sacrificing acidity.

The area's soils are alluvial, deposited over time by the San Antonio River. Made up of clay, loam and gravel, they are free-draining and fairly deep in parts.

Many small, boutique producers can be found in the valley making inky, concentrated wines from Petite Syrah, Grenache and Syrah, along with Cabernet Sauvignon.

San Benito AVA

Established on 4 October 1987, the San Benito AVA is located in San Benito County and is part of the larger Central Coast AVA. The San Benito AVA is located among the low rolling hills of northern San Benito County, California. 

One of a cluster of AVAs in this geologically complex, inland area of California's Central Coast AVA, its neighbors are Cienega Valley AVA, Lime Kiln Valley AVA, Paicines AVA and Mt Harlan AVA.  Together these AVAs cover a sizeable tranche of north-western San Benito County, with San Benito AVA at the northern end, just outside Hollister, the county seat.

The San Benito AVA has a moderate climate with cooling breezes from the Pacific Ocean arriving via gaps between the Gabilan Range and the Santa Lucia Mountains, which separate San Benito County from Monterey County and the Pacific coast beyond.  The southern end of the Diablo Range forms the eastern edge of this area, and helps to guide southerly winds down from Monterey Bay.

Significant variations in elevation and soil type mean there are numerous microclimates favoring the growing of grapes.

The San Benito AVA grows a range of different grape varieties, including Pinot Noir, Chardonnay and Merlot.  Most of the region's grapes are sold to wineries in other areas, but there are also small winemakers whose wines are worth seeking out.

San Bernabe AVA

Established on 28 June 2004, the San Bernabe AVA is located in southern Monterey County. It is part of the larger Monterey AVA. San Bernabe AVA is located in the Salinas Valley, between the Salinas River on the east, and the Santa Lucia Mountains on the west. To the north of the appellation is Pine Canyon AVA and to the south is the San Lucas AVA.

The San Bernabe AVA covers a 24,796 acre tract of land that extends from the Salinas River in the east to the foothills of the Santa Lucia mountains in the west. San Bernabe is open to the cooling breezes and sea fogs that are funneled down the Salinas Valley from the cold Monterey Bay, but it is far enough down the valley that these influences are only moderate.

There are a range of microclimates in San Bernabe AVA, ranging from cooler conditions in the northern part of the vineyard (where the ocean influences are more pronounced) to warmer conditions in the south. Temperature can vary up to five degrees from the north to the south end of the site.

The AVA is home to both warm and cool climate varieties: not many vineyards in the world boast plantings of both Riesling and Zinfandel. The combination of warm days and cool nights across the whole area leads to a longer growing season, allowing grapes to develop varietal character while retaining acidity.

The San Bernabe AVA is home to a diverse array of soil types, with sandy loam being the most prevalent. These sandy soils are free-draining, causing the vines to develop deep root systems, leading to healthier, stronger plants to produce concentrated flavor components.

There are roughly 8,500 acres of vineyard planted in San Bernabe AVA with more than 20 varietals that can be found there, from the classic Californian growers' favorites of red varietals such as Pinot Noir, Cabernet Sauvignon and Merlot, and white varietals such as Chardonnay, Riesling along with some more unusual varietals of Malvasia, Barbera and Lagrein.

San Francisco Bay AVA

Established on 19 January 1999, the San Francisco Bay AVA is a large AVA within California's Central Coast AVA and is centered on the San Francisco Bay Area of Northern California.  The San Francisco Bay AVA includes the counties of Alameda, Contra Costa, Santa Clara, San Francisco and San Mateo as well as parts of Santa Cruz and San Benito counties. 

The San Francisco Bay AVA encompasses over 1,500,000 acres with roughly 4,215 acres planted to grapevines. The AVA falls within the larger Central Coast AVA and contains five other designated AVAs within its boundaries; Lamorinda AVA, Livermore Valley AVA, Pacheco Pass AVA, San Ysidro District AVA, and Santa Clara Valley AVA.

The northern point of the AVA lies to the Northeast of San Francisco city in Solano County on the border with the Solano County Green Valley AVA, with the Golden Gate Bridge the northernmost point of the AVA along the coast. Contra Costa County and Livermore Valley lie to the east of the wider bay.  Santa Clara County and the Santa Cruz mountains are in the south. Pacheco Pass AVA, sitting at the very southern end of the Santa Clara Valley, marks the southernmost extent of the AVA and spills over into San Benito County.

San Francisco Bay itself is an incredibly important watershed in California wine country. The Napa, Mokelumne, Sacramento and Russian rivers all empty into the bay, and the famous AVAs of Napa, Sonoma, Lodi, Yolo County and Solano County all enjoy cooling oceanic influences.

This large AVA is extremely diverse in terms of terroir, but fog and wind from the cool waters of San Francisco Bay (and Monterey Bay to an extent) unite the region somewhat.  These ocean influences are particularly pronounced in the more coastal regions of Santa Cruz and Contra Costa County, but Livermore Valley and Santa Clara Valley are subject to ocean breezes as well.

The effects of warm sunshine are tempered by the breezes, leading to a long ripening season during which grapes can develop complex flavors and aromas while retaining acidity.  Consequently, wines produced in the San Francisco Bay AVA are complex and well balanced, and most of the AVAs here are associated with high quality.

There is an array of different soil types across the region. Contra Costa County's deep, sandy soils are a point of much pride for grape growers, offering little resistance to wandering root systems which are able to reach deeply into the ground.  Santa Clara County and Livermore Valley have more gravelly soils, with the latter enjoying pockets of sandstone and shale.

The high-altitude Santa Cruz Mountains AVA has thinner, more mountainous soils – mostly comprised of shale and decomposed limestone – than the rest of the region.  These dry soils stress the vines, which are then forced to forgo leafy vegetation in favor of small, concentrated fruit.

Nowadays, urban expansion has forced many a grape grower's hand – large producers have moved north into Napa and Sonoma, and many smaller producers have taken to the hills surrounding the valleys.

Cabernet Sauvignon is the most widely planted variety of San Francisco Bay followed by Merlot, Zinfandel, Pinot Noir and Chardonnay. Varieties across the region are as diverse as its geography, however.

San Juan Creek AVA

Established on 8 October 2014, the San Juan Creek AVA is located in San Luis Obispo County on California's Central Coast.  The designated area largely encompasses the valley floor of San Juan Creek surrounding the city of Shandon, including a narrow 10 mile stretch of land that runs along the northeast border of the Paso Robles Highlands District AVA.

The San Juan Creek AVA within the greater Paso Robles AVA may be the oddest shaped of the 11 AVAs in Paso.  In large part, because it follows the San Juan Creek Valley that represents the easternmost AVAs as it touches the Paso Robles Estrella District AVA to its north and the Paso Robles Highlands District AVA to its south.

San Juan Creek AVA lies south of the Cholame Hills, which increase in elevation and incline as they head into the Temblor Range.  Because San Juan is shielded by both the Santa Lucia and the Temblor Ranges it is not significantly influenced by the Pacific Ocean, having a climate that leans more towards continental characteristics than other more westerly parts of Paso Robles.

The San Juan Creek AVA consists of about 26,000 acres with a little over 3,000 acres under vine. Elevations in the district range from 980 feet to 1,600 feet above sea level, from river valleys to foothills, respectively. The landscape of the district is evident from the effect of the San Andreas Fault and adjacent San Juan Fault. There is a lot of uplift and subsequent erosion of the mountain ranges.

The San Juan Creek AVA is about 32 miles from the Pacific Ocean and within a rain shadow of the Santa Lucia Coast Range, so it has a warmer and more continental climate than some of the other Paso Robles AVAs to the west. There is a descending air movement that takes place in the rainy season down the lee slopes of the coastal range, as well as the La Panza Range to the south. As a result, rainfall decreases from about 20 inches annually in the Templeton Gap District to around 10 inches in the San Juan Creek AVA. That is a 50% reduction in rainfall in less than 20 miles.

San Juan Creek AVA can get exceptionally warm during the summer as it is a Region III – IV on the Winkler Scale, although the nights still get quite cool with an average diurnal temperature swing of 35 – 40 degrees Fahrenheit. 

The broad alluvial plain of the San Juan Creek AVA consists of mostly loamy sands, gravelly to sandy clay loams, and a few clays on the older alluvial fans and terraces.  These create moderately draining conditions in the vineyards which encourage moderate vigor in the vines.  This also provides an environment for deep soil rooting depths and some moderate to high water stress.

The drier and warmer growing days with high temperature ranges mean that the vines in San Juan have a shorter growing season and harvests typically take place earlier in the season than neighboring AVAs.  Moderate yields are common with these earlier harvest dates than in the cooler regions to the west.

This growing degree climate in the San Juan Creek AVA is suited to several Bordeaux varieties of wine grapes, including Cabernet Sauvignon, Merlot, Syrah and Cabernet Franc. However, many are seeing success with Petite Syrah and some Italian and Spanish varieties as well. 

San Lucas AVA

Established on 28 January 1987, the San Lucas AVA is located in Monterey County. It is located at the southern end of Salinas Valley, shares an eastern border with the Chalone AVA, and is bordered on the west by the Santa Lucia Range foothills.

Being that San Lucas AVA is at the southeastern end of the Salinas Valley, it is effectively within the Monterey AVA in the wider Monterey County of California.  The wider Monterey AVA continues up the valley for about 10 miles before its end, which overlaps, to a degree, with the Hames Valley AVA.

The San Lucas AVA is about 33,920 acres in size and has around 8,000 acres of vineyards.  It includes vineyards on both sides of the Salinas River, although most plantings are on the west.

San Lucas AVA is less windy than the more northern regions in Monterey – it is far enough south to avoid the influence of the strong winds that are funneled through the Salinas Valley from Monterey Bay.  As a result, the day-time temperatures are warmer here than in other parts of the valley. However, the region is still subject to morning fog and some afternoon breezes.

Evening temperatures are much lower than those during the day, giving the grapes overnight respite from the heat and lengthening the ripening period.

The San Lucas AVA has the largest diurnal temperature variation of any of California's AVAs.  A longer ripening period means that grapes have time to develop varietal character while retaining vital acidity.

The region has a range of free-draining soils, including calcareous chalk rock, loam and sandstone. Generally, this is classified as a shaly-loam area.  This soft, fractured rock lets root systems penetrate the ground deeply with little resistance, giving strength to the vines and limiting vigor and yields. The vines are thus able to put more energy into producing grapes with excellent concentration.

As one of Monterey's warmer wine regions, San Lucas AVA produces rich, concentrated red wines made from Cabernet Sauvignon and Merlot and fruit-driven, tropical white wines made from Sauvignon Blanc and Chardonnay.

San Luis Obispo Coast AVA

Established on 8 March 2022, the San Luis Obispo Coast AVA is a key portion of the Central Coast of California.  Stretching from the border of Santa Barbara County to the Monterey County Line, the San Luis Obispo Coast AVA includes all vineyards within this 15-mile swath, bordered by the Pacific Ocean and the Santa Lucia Mountains.  The Santa Lucia mountain range marks the eastern boundary of the San Luis Obispo Coast AVA and separates it from the warmer AVAs on the inland side of the mountains.

The majority of the San Luis Obispo Coast AVA is classified as “Region 1,” indicating it is one of the coolest winegrowing areas in the world, and the coolest within California. Billowing morning fog gives way to warm afternoon sunlight. Come evening, a salty breeze rustles through the vines.  The vines count on this reliable cooling and warming cycle to maintain the long growing season–one of the longest in the world.

The pronounced marine conditions and moderate temperatures allow the fruit to achieve rich, full flavors while maintaining their natural acidity, structure, and balance.

Approximately 17 million years ago, the current soils of the San Luis Obispo Coast AVA were forged during the collision of the Pacific and Continental plates.  This sheer force caused the commingling of the region’s unique seabed soil of marine shale, sand, and fossilized shells with the volcanic soil of the area’s distinctive morros, together forming a rare soil complexity that often varies from acre to acre.

The soils are lean and shallow, well-draining with hard bedrock below, putting vines through just the right amount of stress to produce amazingly complex fruit with intense color and flavor.

Just 5,000 total vineyard acres planted in the San Luis Obispo Coast AVA.  Over 20 grape varieties flourish on the SLO Coast.  Particularly Burgundian varieties and cool-climate favorites Pinot Noir and Chardonnay, the SLO Coast also makes an excellent home to aromatic white varieties such as Pinot Gris, Riesling, and Gewürztraminer. Rhône varieties, such as Syrah and Viognier, are also among the favorites found on the SLO Coast. And in the warmer, mountainous areas, Zinfandel, Cabernet Sauvignon, and Merlot have been growing strong for decades. The diverse fruit of the SLO Coast is united by an energetic acidity and vibrancy only achieved via the unique set of growing conditions.

Other varietals have also been experimented with.  Albariño is a varietal that seems to have found a home in the SLO Coast AVA, with 20% of California’s acreage of Albariño found here. It thrives in the cool, coastal climate and results in a fresh style with bright acidity and showcases the salinity typical of the varietal.

San Miguel District AVA

Established on 8 October 2014, the San Miguel District AVA is the northernmost AVA of the greater Paso Robles winegrowing region in California's Central Coast. It encompasses the area around the town of San Miguel in San Luis Obispo County.  The total area covers more than 18,500 acres, with altitude between 580 and 1,600 feet.

The San Miguel District AVA is the northwestern-most of the 11 AVAs of Paso Robles. Its northern boundary is the county line between Monterey and San Luis Obispo. It is bisected by the Salinas River which flows to the north and empties in Monterey Bay. There is also the confluence of the Estrella River and Nacimiento River, at differing locations, into the Salinas River within the San Miguel District AVA.  The District’s western border is largely made up of steep mountains of the Santa Lucia range and Camp Roberts military base. Its eastern edge lines up with the western edge of the Paso Robles Estrella District AVA. Both the Adelaida District AVA and the Paso Robles Estrella District AVA stair-step the southern border.

The undulating topography here is created by the foothills of the Santa Lucia Range, which runs for 105 miles from Monterey County into San Luis Obispo, and the convergence of the Salinas and Estrella rivers. This creates ideal landscape for viticulture with vineyards found planted on sites with a favorable aspect to maximize sunshine hours.

The climate of the San Miguel District AVA, as compared to the rest of the Paso Robles AVA, is the windiest, warmest, and driest.  Portions of the easternmost AVAs could compete for this trifecta title as averages can vary.  However, a keen eye of the natural vegetation of the region reflects the growing conditions well as there are scattered oaks across grassy hillsides and denser growths of trees and shrubs along the creek and river valleys.  The San Miguel District AVA lies directly adjacent to the rain shadow of the Santa Lucia range, which can drastically reduce the amount of rainfall it receives.  There is also a lessened maritime influence in the San Miguel District AVA, much to do with its location near to the higher northern range and out of the window of the Templeton Gap effect to the south where the range tops out at a slightly lower elevation.

The San Miguel District AVA receives an average annual rainfall of 11.4 inches of which a majority is concentrated to the winter months.  There is less influence here from the Pacific Ocean and its cooling effects by way of the Templeton Gap, especially in comparison to the more southerly regions of Paso Robles. 

Many creeks and rivers dominate the landscape of the San Miguel District AVA.  These waterways bring deep, alluvial sandy loams to a few clay loams (some with claypans) from the river and creek bottoms up onto the higher terraces.  Alluvial soils dominate the region and reflect the material’s origins with mixed sediments of carbonates, silicates, and iron, as well as granite and shale. Most vineyards are planted within the elevations of 640 to 1,000 feet above sea level. The soils at lower elevations can retain moisture, thus encouraging more vigor in vines. Higher elevations will have less topsoil onto bedrock, reducing vigor and elevating concentration. In all the climate along with soils see earlier maturation of fruit in the region.

Wine grapes have been planted in the San Miguel District AVA since the earliest recording of viticulture in the region.  The predominant grape varieties planted are in line with the greater Paso Robles viticultural area with red wines dominating led by Cabernet Sauvignon and Merlot.  Zinfandel makes up a notable amount followed by southern Rhone red varieties such as Grenache, Syrah and notably Mourvèdre, a variety that does well in warm, dry climates.

San Ysidro District AVA

Established on 14 November 1990, the San Ysidro District AVA is located in Santa Clara County. Located in the foothills of the Diablo Range and lying just south of the town of Gilroy, San Ysidro also falls within the Santa Clara Valley AVA with the Pacheco Pass AVA found to the southeast.

Covering 2,340 acres at the base of the Diablo Hills, San Ysidro District AVA is at the southern end of the Santa Clara Valley. 

San Ysidro District AVA is significantly cooler than other parts of Santa Clara Valley due to the winds that are funneled through the Pajaro River Gap from Monterey Bay to the west. The deep ocean canyon that runs through Monterey Bay means that the water here is much colder than in San Francisco Bay in the north, and the winds and fog that come from the bay are colder than other Pacific winds in California.

The winds sweep through the vineyards in the afternoon, helping to negate the effects of the morning's warm sunshine. Vineyards are planted on slopes that face southwest, giving them all-day exposure to the sun.

Soils in San Ysidro District are usually made up of sandy loam and clay. This soil profile allows for excellent drainage while still offering good water retention.  Water runs freely through the sand, keeping the root systems nice and dry, but enough moisture is absorbed by the clay to keep the vines hydrated. Vines grown in free-draining soils produce smaller, more-concentrated berries because there is less water to dilute flavor.

In all, this ensures that San Ysidro District AVA grapes have a longer growing season and can develop rich flavors and aromas while retaining precious acidity. 

The San Ysidro District AVA predominantly supplies quality Pinot Noir, Chardonnay and Merlot grapes to wineries in other parts of the Central Coast.  The San Ysidro District AVA title is rarely seen on wine labels.

Santa Clara Valley AVA

Established on 27 March 1989, the Santa Clara Valley AVA is located mostly in Santa Clara County but also covers portions of Alameda County, San Benito County, and San Mateo County.  Santa Clara Valley AVA extends south from San Francisco Bay along the edge of the Santa Cruz Mountains.

A part of the larger San Francisco Bay AVA, the Santa Clara Valley AVA spans 332,800 acres and stretches roughly 70 miles south from San Francisco.  The AVA encompasses the towns of San Jose, Sunnyvale and Saratoga, but most wine production takes place in the southern end of the valley around the town of Morgan Hill, at the entrance to the perpendicular Uvas Valley.  The Santa Clara Valley AVA is home to two smaller AVAs, Pacheco Pass AVA and San Ysidro District AVA.

Urban sprawl and industrialization in the past 20 years have taken their toll on the wine industry here, and wine production has been pushed into the southern end of the valley. Most wineries are small in size and boutique in nature, although a few larger ones remain in the northern part of the valley. This is not an uncommon situation in California - Contra Costa County, Livermore Valley, and Cucamonga Valley near Los Angeles have all suffered similar fates.

Most of Santa Clara Valley AVA's vineyards can be found in the eastern foothills of the Santa Cruz mountain range, and benefit from a variety of aspects and inclines that take advantage of prevailing sunlight.

Santa Clara Valley AVA is relatively warm by San Franciscan standards, due to the sheltering influence of the Santa Cruz mountains.  The climate can be classified as Mediterranean, and the region enjoys warm days and moderate evenings, cooled by sea breezes from the San Francisco Bay. Early-morning fog settles in the vineyards of Santa Clara Valley AVA, helping to cool the grapes before burning off later in the day. These ocean influences serve to extend the growing season, which helps grapes to achieve phenolic ripeness while retaining a good level of acidity.

Soils in the area are generally made up of gravelly loam, clay and sandstone. These free-draining soils are excellent for vineyards – by limiting water intake, they cause stress in the vines, leading to less vigor and lower grape yields.

Santa Clara Valley AVA is home to some of the oldest Zinfandel vineyards in California. Cabernet Sauvignon, Merlot, Chardonnay and Sangiovese can also be found in the valley. 

Santa Lucia Highlands AVA

Established on 14 May 1992, the Santa Lucia Highlands AVA is located in Monterey County. It is part of the larger Monterey AVA, and located in the Santa Lucia Mountains above the Salinas Valley.  Santa Lucia Highlands AVA is a long, narrow AVA that runs down the western side of the Salinas Valley in Monterey.

The Santa Lucia Highlands AVA covers an area that runs southeast along the foothills of the Santa Lucia mountain range, stretching from the town of Gonzales to the neighboring Arroyo Seco AVA in the south. Vineyards are planted on south and east facing hills, often at elevations of up to 1,200 feet.  Over 2,300 acres of vineyards are planted in the Santa Lucia Highlands AVA.

The influence of the Pacific Ocean plays a major part in the climate of the Santa Lucia Highlands AVA.  The elevated slopes are subject to bright morning sunshine, and coastal breezes that sweep down the Salinas Valley from Monterey Bay to provide a counter to this in the afternoon. Reaching gusts of up to 25 miles an hour, the wind retards photosynthesis and forces grapes to develop a thicker skin, contributing higher tannins and phenolic structure to the finished wines produced in the area.

Nighttime and morning fogs also provide cooling influences, creating a classically cool-climate viticultural area with a long ripening period.  In fact, the Santa Lucia Highlands AVA has one of the longest growing seasons in California, with harvest sometimes following the rest of the state by up to six weeks. This long growing season means that grapes can ripen slowly and evenly, developing complex varietal character and fresh acidity.

The soils in the Santa Lucia Highlands AVA are well-drained with low fertility, making them perfect for the production of premium grapes.  The combination of the soils and the exposure to wind stresses the vines, causing them to put all their energy into the production of fruit rather than the canopy.  The resultant berries are small with thick skins, leading to great structure and depth of flavor in the wines.

The Santa Lucia Highlands AVA has earned a reputation for intensely flavored Chardonnay and weighty Pinot Noir.  It is also synonymous with the Burgundy varieties, but excellent examples of Riesling and even some Northern Rhône-styled Syrah can be found here.

Santa Margarita Ranch AVA

Established on 8 October 2014, the Santa Margarita Ranch AVA is one of 11 specific designated sites within the wider Paso Robles viticultural area on California's Central Coast.  Santa Margarita Ranch AVA is the southernmost of the Paso Robles sub-regions and is the only territory not adjacent to any other AVAs.

The Santa Margarita Ranch AVA is quite possibly the most unique of all the 11 Paso Robles districts.  The Santa Margarita Ranch AVA encompasses an area of approximately 18,300 acres.

It is at the southern boundary of the Paso Robles AVA, nestled up against the Santa Lucia Mountain Range. It stands alone, meaning that its boundaries do not border any of the other Paso Robles districts.

The headwaters of the Salinas River, which helps to define the greater Paso Robles AVA, begin in the surrounding mountains and feed the river from the spillway of Santa Margarita Lake. As the river runs to its northern mouth on Monterey Bay, its origins trace the northeast boundary of the Santa Margarita AVA.

The region of Santa Margarita Ranch AVA mostly encompasses a valley floor surrounded by hills ascending to higher elevations. Altitude here ranges from 900 to 1,400 feet, with the majority of vineyards being located on the valley floor.  Santa Margarita Ranch AVA is too far south to be affected by the Templeton Gap, but cool ocean breezes and the occasional coastal fog enter through the Cuesta Pass, a more southerly series of gaps in the peaks of the Santa Lucia Range.

The overall marine influences on the valley are modest, but it still has the high annual rainfall average of 29 inches. Santa Margarita Ranch AVA is capable of warmer days and cooler nights than other regions of Paso Robles creating a longer growing season for grapes to reach full ripening potential. Unfortunately, cold air draining from higher elevations can pool making frost a serious concern and challenge for growers. 

The soils of the Santa Margarita Ranch AVA also include a series of sandy loam to loam soils in the floodplains of the creeks, which are abundant within the valley. They also include gravelly loam soils on the terraces and clay loams on the highest terraces and hillside as well as pockets of clay soils in some of the low-lying areas. The diversity of soil types reflects the landform age and the parent material type, which is largely Monterey Shale, as well as, its own Santa Margarita sandstone. A curiosity in the region lies within the Santa Margarita Ranch AVA at the Oyster Ridge where large, fossilized oyster shells are abundant. This is reflective of an ancient shallow seabed that allowed oysters to thrive into exceptionally large specimens.

There are at least 16 varieties of wine grapes planted in the Santa Margarita Ranch AVA.  Syrah has played a pivotal role here, with Cabernet Sauvignon, Zinfandel, Merlot and Chardonnay also featuring heavily of the grape inventory.

Santa Maria Valley AVA

Established on 4 August 1981, and expanded in 2011, the Santa Maria Valley AVA is located in the northernmost part of Santa Barbara County and straddles the boundary of Santa Barbara and San Luis Obispo counties in California's multi-county Central Coast AVA.  A portion of the AVA crosses the Cuyama River into the southernmost corner of San Luis Obispo County.

The Santa Maria Valley AVA is bounded by the San Rafael Mountains and Los Padres National Forest to the east and by the Solomon Hills and the city of Santa Maria to the West.  The elevation of the area ranges from approximately 200 feet at the intersection of Highway 101 and the Santa Maria River to approximately 3,200 feet at Tepusquet Peak.  The east–west orientation of the 116,273 acres with a wide, open valley and rolling hills means cool winds and fog flow in freely from the Pacific Ocean, settling most noticeably in lower-lying areas.

The Santa Maria Valley AVA geography channels dense banks of morning fog from the Pacific Ocean that takes many hours to burn off, only to be replaced by chilly afternoon breezes. This “maritime fringe” climate lengthens the growing season and contributes to the eventual sugar/acid balance in the grapes from the region. Summer in the Santa Maria Valley is goose-bump season, with an average summer temperature of only 75 °F. 

The result is a Mediterranean climate that produces one of California’s longest growing seasons. The unique growing environment ensures the development of complex, flavorful and exquisitely balanced grapes from Santa Maria Valley's 7,500 acres cultivated vineyards. Grapes in the region are either grown on the Santa Maria Bench or off the Bench, both wine grapes with completely different and unique flavor profiles.

This is a growing environment that is a Region I on the Winkler Scale. As with most of Santa Barbara County, annual rainfall is very low in the Santa Maria Valley. The AVA averages less than 14 inches in non-drought years. Vines typically require 20–30 inches of water per year for dry-farming, therefore, irrigation is essential.

The low rainfall, mild temperatures and a prolonged growing season are not the only features of the AVA's terroir – the loamy soils are relatively free draining, preventing the vines from becoming waterlogged in almost all conditions. The proportion of sand and/or clay in these loams varies from area to area, depending on the local geology. Limestone is present in some of the region's most exceptional vineyard plots.

The soils range in texture from a sandy loam to clay loam and are free from adverse salts. Soil variation can broadly be cut into four types. Three types are within the original Santa Maria Valley AVA: the Valley floor, the Solomon Hills, and the foothills of the Sierra Madre Mountains, northeast of the Santa Maria River. The fourth is the southern expansion area.

Along the northern portion of the Santa Maria-Sisquoc River colluvial soils cover slope sides giving rocky freshness to grapes grown throughout. Towards the river side, soils become unconsolidated as mixed alluvial soils appear. The soils are mainly sand, sandy loam, and loam on the valley floor, but are mixed sandy, clay, shaly and silt loams on mountain slopes. However, the soils in the expansion area are the same type as in the original Santa Maria Valley area. In the expansion area and on hills in the original viticultural area, the soils are sand, sandy, clay, and shaly loams.

The cool maritime influence lengthens the growing season and contributes to the balance of sugar/acid in the wine produced here. Santa Maria Valley's extended grape-growing season is among the longest in the world.  The grapes that are grown within the area are on the valley floor at an approximate elevation of 300 feet and on the slopes and rolling hillsides up to an elevation of 800 feet.

The dominant grape variety planted in Santa Maria Valley's Pinot Noir of which does particularly well in the AVA's cooler microclimates.  Leaner, more elegant styles of Pinot Noir are made from vines planted at higher elevations (more than 600ft) at the eastern end of the valley, in the peripheries of the fog line.

Chardonnay, is also widely planted throughout the AVA and is the grape variety behind roughly one-third of Santa Maria Valley's white wines. Warm-climate varieties, too, are represented in the valley, led by the classic northern Rhône grape varieties of Syrah and Viognier. Grenache and even Marsanne are also cultivated, although only in very small quantities. 

Santa Ynez Valley AVA

Established on 14 April 1983, the Santa Ynez Valley AVA is located in Santa Barbara County. It is part of the larger Central Coast AVA.  The Santa Ynez Valley AVA contains four other established viticultural areas: Sta. Rita Hills AVA on its western boundary; Ballard Canyon AVA and Los Olivos District AVA occupying the center region; and Happy Canyon of Santa Barbara AVA on the eastern border. 

The Santa Ynez Valley AVA is formed by the Purisima Hills and San Rafael Mountains to the north and the Santa Ynez Mountains to the south creating a long, east-west corridor with very cool temperatures on the coast that become progressively warmer inland. The Santa Ynez River flows east to west on the valley floor toward the Pacific Ocean.

The Santa Ynez Valley AVA fills a wide, east-west-oriented valley along the course of the Santa Ynez River, stretching from the Sta. Rita Hills AVA and the Purisima Hills in the west to Lake Cachuma in the east. The area is bordered in the northeast by the San Rafael Mountains, while the Santa Ynez Mountains lock in the southern part of the AVA.

The Santa Ynez Valley AVA narrows at its western extreme where it edges towards the Pacific Ocean coastline, and it is through this narrow gap that ocean influences permeate into the vineyards.  The cooling influences from the ocean reduce moving eastwards through the valley.  Overall, Santa Ynez Valley AVA has warmer temperatures than in the rest of Santa Barbara County, but is still relatively cool compared to the inland regions of the Central Valley and the Sierra Foothills.  The ocean fog and winds help to reduce overnight temperatures and extend the growing season, leading to balanced wines with a good level of acidity.

Soils here are considerably more marine than in other parts of the state, being the remains of an ancient sea bed.  The soils range from sandy loams at the base of the valley, to the silty, clay and shale loam soils found at higher elevations at the foot of the valley's steep hillsides. These free-draining, shallow soils are well suited to viticulture as they cause stress in the vines, which leads to low vigor and yields, as well as berries with concentrated flavor.

Vineyards in the western end of the valley are suited to the cooler-climate varieties of Pinot Noir, Chardonnay and, occasionally, Riesling.  The eastern end therefore has more plantings of grape varieties including Cabernet Sauvignon, Merlot, Sauvignon Blanc and Syrah.

Sta. Rita Hills AVA

Established on 30 May 2001, the Sta. Rita Hills AVA is located in Santa Barbara County.  Sta. Rita Hills AVA located at the western end of the Santa Ynez Valley in California's Central Coast wine region.  Sta. Rita Hills AVA is part of the larger Santa Ynez Valley AVA, located between the towns of Lompoc and Buellton with the Purisima Hills on the north and the Santa Rosa Hills on the south.  The AVA stands at approximately 36,000 acres.

The vineyards in Sta. Rita Hills AVA benefit from the Pacific Ocean's cooling influences on three sides with the coast 16 miles away to the west, south and southeast. With a latitude of 34 degrees north, Sta. Rita Hills AVA lies closer to the equator than any European wine region.

The wine region is exposed to fog and coastal breezes from the nearby Pacific Ocean. The hills run east to west, which allows cool ocean breezes from the nearby Pacific Ocean to enter the valley created by the hills and create a cool microclimate.

These strong maritime influences keep daytime temperatures here within bearable limits. The AVA's coastal valleys, formed by the presence of the Purisima Hills to their north and the Santa Rosa Hills to their south, funnel the cool Pacific breezes up through the vineyards.

This ventilation reduces the incidence of fungal infections, whilst cooling the vines down in the hot afternoon sunshine.  Fog also acts as a climatic moderator, lowering the temperatures during the hot summer months. The combined effects of the ocean breezes and fog significantly extend Sta. Rita Hills AVA's growing season, giving its grapes extra time to develop full phenolic ripeness.

The soils in the Sta. Rita Hills are in the main formed of loams: sandy loams, silt loams and clay loams. Marine deposits are also widely found, giving the wines noticeable minerality and salinity. These poor, free-draining soils, in combination with the region's low annual rainfall, also imbue the wines of Sta. Rita Hills with good natural acidity.

The vineyards are overwhelmingly planted to Pinot Noir, with Chardonnay ranking second, followed by smaller plantings of Syrah, Sauvignon Blanc, Viognier and other grape varieties. 

Templeton Gap District AVA

Established on 8 October 2014, the Templeton Gap District AVA is one of 11 designated AVAs within the larger Paso Robles AVA on California's Central Coast.  The geology of the Templeton Gap District AVA is essentially a result of uplift from the Santa Lucia Range west of the Rinconada fault.  Altitude here ranges from 700 to 1,800 feet.

The eastern slope of the Santa Lucia Range dramatically rises from the Salinas River, forming the western and northern boundaries of the district. As you travel east in the district, the Salinas River and various creeks have down cut into channels and floodplains, resulting in the exposure of higher alluvial terraces and fans set above the river channels. Sloping hills and cuestas frame the district to the south.

The Pacific Ocean is approximately 18 nautical miles to Paso Robles from its closest point being the town of Cayucos, which sits at the inner apex of Estero Bay. The western border of the Templeton Gap District AVA is much closer and as the marine layer builds across Estero Bay to altitudes of 1,400–1,800 feet, the heavier marine air spills across the range crest, easily depicted by large fingers of fog reaching over the mountains.  This cool air spills through the gap along the Highway 46 West corridor and continues to flow to the lower elevations to the east, across the Templeton Gap District AVA, and into the El Pomar District AVA, Creston District AVA, and the Paso Robles Estrella District AVA.

Although cooling breezes can find their way inland up and down the coastal range, it is the aligning of factors that create the very specific Templeton Gap effect that helps to not only cool off the Templeton Gap District AVA but many other parts of the greater Paso Robles AVA. There is a slight overall topographic elevation drop that aligns with Estero Bay, as well as east to west ravines that are conducive to channeling airflow. Although Estero Bay does not have a submarine canyon, water remains cold year-round, adding to the climatic uniqueness of the region through advection fog, which is the combination of a cool surface mixing with warm moist air.

Because of this accelerated airflow through the gap, the Templeton Gap District AVA is windier than much of the rest of the Paso Robles AVA. It also sits up against the mountain range and extends to the east with lower elevations, well within the rain shadow of the mountains. This results in an approximate average of 20 inches of rain per year.

The warm days of Paso Robles have a direct cause and effect on this cooling influence. As the temperature gradient rises a vacuum effect pulls the spilling cool air inland and like clockwork, by 3 p.m. the cool breeze begins.  The cooler climate lengthens the growing season so that vineyards within the Templeton Gap District AVA typically harvest grapes 10-14 days later than other Paso Robles AVAs.

The Templeton Gap District AVA is a region Type II according to the Amerine and Winkler scales, which in essence puts it at about an average of 2,900 growing degree days. This is equivalent to other growing regions like the Duoro Valley, Piedmont, and Bordeaux, which are also in the 2,900 range.

Soils in the Templeton Gap District AVA are high in calcaerous material with vineyards found planted on the pockets with a deep soil profile. This allows vines to grow deep, well-established root systems that are able to maximize their exposure to any soil moisture content.  Some of the soils have slightly acidic topsoils with pH values of 6.1 to 6.8, others are neutral to slightly alkaline even at the surface with pH values of 7.0 to 7.8. As a result, natural acidity abounds in much of what is grown in this region.

Similar to much of Paso Robles AVA, Syrah and southern Rhône varieties are successful, as well as Zinfandel and the white grape Viognier. The region is also known for its Cabernet Sauvignon and Bordeaux-style blends.

York Mountain AVA

Established on 23 August 1983, the York Mountain AVA is located in San Luis Obispo County. It is part of the larger Central Coast AVA, located on the eastern side of the Santa Lucia Mountains, west of Paso Robles AVA, and just 8 miles from the Pacific Ocean.

The mountainous AVA covers an area of 6400 acres at the opening of the Templeton Gap, a channel in the Santa Lucia mountains that draws cooling marine air into Paso Robles. York Mountain AVA's vineyards all sit at fairly high altitudes of around 1500 feet.

York Mountain AVA is much cooler and wetter than the rest of San Luis Obispo County. Long, sunny days during summer are followed by considerably cooler nights, caused by the cold air and fog that are provided by the Pacific Ocean, just eight miles away. This diurnal temperature shift serves to lengthen the growing season and translates to balanced grapes with good acidity and varietal character.

The soil is made up of chalky limestone. Thin and of low fertility, it is perfect for the production of wine. The rocky soil composition causes stress in the vines, limiting vigor and yields and leading to more concentrated wine.

Overall, York Mountain AVA has a cool, maritime climate, which is well-suited to the production of elegant, brooding red wines made from Pinot Noir, Cabernet Sauvignon and Syrah.

Ben Lomond Mountain AVA

Established on 8 December 1987, the Ben Lomond Mountain AVA is in Santa Cruz County.  On the western edge of the Santa Cruz Mountain AVA, the Ben Lomond Mountain AVA covers an area of nearly 40,000 acres in the western Santa Cruz Mountain range.

The area surrounds the towns of Ben Lomond and Bonny Doon, and the Pacific Coast is on the western edge of the appellation.  The Ben Lomond Mountain AVA ranges in altitudes as high as 2,600 feet above sea level to 1,300 feet, placing it between the fog that rolls in from the Pacific Ocean, ensuring long hours of sunlight and a long growing season.

The Ben Lomond Mountain AVA is differentiated from the surrounding area by the factors that affect its cool climate – namely altitude and close proximity to the ocean. Most of the vineyards of Ben Lomond Mountain AVA are between 1,300ft and 2,000ft above sea level, well above the fog that shrouds the lower areas of Santa Cruz. Vineyards are planted on south-facing slopes to maximize the warm sunshine during the day.

Despite this, the region is not free of cooling oceanic influences. With the farthest edge of the AVA just eight miles from the ocean, Ben Lomond Mountain AVA experiences cold winds from Monterey Bay, which reduces temperatures in the area. This, combined with the altitude of the mountain vineyards, leads to a significant diurnal temperature variation, where warm days are followed by cold nights. This extends the growing season, giving the grapes time to develop ripe fruit flavors without sacrificing acidity. As a result, wines of Ben Lomond Mountain AVA tend to be bright and fresh, with a firm structure.

There is an array of soil types in the Ben Lomond Mountain AVA due to the presence of several fault lines, but vineyards can usually be found on eroded granite and sandstone soils, with some pockets of limestone. These soils drain freely, leading to a lack of water in the soil that stresses the vines which in turn lowers yields and reduces vigor.

Vineyards were first planted in the Ben Lomond Mountain AVA in the 1860s sitting at a premium spot for grape growing.  Elegant, balanced wines made from Pinot Noir and Chardonnay are a specialty of the area;  Cabernet Sauvignon and Zinfandel count among the grape varieties which are also grown here.

Santa Cruz Mountains AVA

Established on 3 December 1981, the Santa Cruz Mountains AVA is centered on the Santa Cruz Mountains. Its territory expands across parts of three California counties, Santa Clara, Santa Cruz and San Mateo.  The region is bounded by the Santa Cruz Mountain range, from the northern boundary of Half Moon Bay and Woodside to its southern side of Mount Madonna and Watsonville. The appellation encompasses some 322,000 acres.

Based on elevation, the Santa Cruz Mountains AVA largely follows the fog line along the coast, extending down to 800 feet on the eastern slope toward San Francisco Bay, 400 feet on the western slope to the Pacific Ocean and extending toward the ridge crests at 3000+ feet elevation.

The mountainous terrain, the Pacific Ocean, and the nearby San Francisco Bay have wide-ranging effects on the appellation, creating myriad microclimates in the region - depending on the elevation of the land, on which side of the mountains are the vineyards, the effects of fog, sun exposure, soil type, etc.  The Santa Cruz Mountains AVA's subregions are Skyline, Saratoga/Los Gatos, Summit, the Coastal Foothills (above Santa Cruz), Ben Lomond Mountain AVA, and Corralitos/Pleasant Valley.

Individual and site-specific microclimates are an important part of the terroir here. Vineyards planted on western slopes feel the cooling effects of strong winds from the Pacific Ocean. Further inland, vineyards planted on east-facing slopes get some protection from the ocean and are therefore much warmer.

Much like the mountainous Mendocino Ridge AVA in the north, the region's best vineyards are planted on steep ridges well above the reaches of the fog that covers the lower valleys. Exposure to intense sunlight is cooled by prevailing ocean breezes, creating a long, cool growing season. The resultant wines have rich varietal character and firm, structured acidity.

Several fault lines run through the Santa Cruz Mountains, resulting in significant variations in the largely thin and infertile soil – even from one vineyard to the next. Soils made of clay and Franciscan shale can be found layered over bedrock made of decomposing limestone.

The combination of these free-draining soils and the exposure to wind and sunshine causes stress in the vines, leading to small, concentrated berries and lower yields.

Roughly 1,500 acres of the Santa Cruz Mountains AVA are planted to vineyard, encompassing a range of wine grape varieties, divided about ¼ evenly among Pinot Noir, Cabernet Sauvignon, Chardonnay, and other varieties (most notably Merlot and Zinfandel).

Santa Cruz Mountains AVA is the coldest Cabernet Sauvignon-producing region in California. The cool climate - especially closer to the coast - is more classically suited to the Burgundy varieties of Pinot Noir and Chardonnay, which also thrive here.